Compliant solid-state ionically conductive composite materials and method for making same

ABSTRACT

Provided herein are ionically conductive solid-state compositions that include ionically conductive inorganic particles in a matrix of an organic material. The resulting composite material has high ionic conductivity and mechanical properties that facilitate processing. In particular embodiments, the ionically conductive solid-state compositions are compliant and may be cast as films. In some embodiments of the present invention, solid-state electrolytes including the ionically conductive solid-state compositions are provided. In some embodiments of the present invention, electrodes including the ionically conductive solid-state compositions are provided. The present invention further includes embodiments that are directed to methods of manufacturing the ionically conductive solid-state compositions and batteries incorporating the ionically conductive solid-state compositions.

CROSS-REFERENCE TO RELATED APPLICATIONS

An Application Data Sheet is filed concurrently with this specificationas part of the present application. Each application that the presentapplication claims benefit of or priority to as identified in theconcurrently filed Application Data Sheet is incorporated by referenceherein in its entirety and for all purposes.

FIELD OF INVENTION

The invention relates generally to the field of solid-state alkali-ionand alkali metal batteries. More particularly, it relates to ionicallyconductive composite materials and battery components, such aselectrolytes and electrodes, that incorporate the ionically conductivecomposite materials.

BACKGROUND

Solid-state electrolytes present various advantages over liquidelectrolytes for primary and secondary batteries. For example, inlithium ion secondary batteries, inorganic solid-state electrolytes maybe less flammable than conventional liquid organic electrolytes.Solid-state electrolytes can also faciliate use of a lithium metalelectrode by resisting dendrite formation. Solid-state electrolytes mayalso present advantages of high energy densities, good cyclingstabilities, and electrochemical stabilities over a range of conditions.However, there are various challenges in large scale commercializationof solid-state electrolytes. One challenge is maintaining contactbetween electrolyte and the electrodes. For example, while inorganicmaterials such as inorganic sulfide glasses and ceramics have high ionicconductivities (over 10⁻⁴ S/cm) at room temperature, they do not serveas efficient electrolytes due to poor adhesion to the electrode duringbattery cycling. Another challenge is that glass and ceramic solid-stateconductors are too brittle to be processed into dense, thin films. Thiscan result in high bulk electrolyte resistance due to the films beingtoo thick, as well as dendrite formation, due to the presence of voidsthat allow dendrite penetration. The mechanical properties of evenrelatively ductile sulfide glasses are not adequate to process theglasses into dense, thin films. Improving these mechanical propertieswithout sacrificing ionic conductivity is a particular challenge, astechniques to improve adhesion, such as the addition of a solid polymerbinder, tend to reduce ionic conductivity. It is normal to observe morethan an order of magnitude conductivity decrease with as little as 1 wt% of binder introduced. Solid-state polymer electrolyte systems may haveimproved mechanical characteristics that faciliate adhesion andformation into thin films, but have low ionic conductivity at roomtemperature.

Materials that have high ionic conductivities at room temperature andthat are sufficiently compliant to be processed into thin, dense filmswithout sacrificing ionic conductivity are needed for large scaleproduction and commercialization of solid-state batteries.

SUMMARY

The compositions, methods and devices of the present invention each haveinventive aspects. One aspect of the invention relates to a solid-statecomposition that includes an ionically conductive amorphous inorganicmaterial; a first component, wherein the first component is anon-ionically conductive polymer having a number average molecularweight of between 500 g/mol and 50,000 g/mol; and a binder, wherein thebinder is a non-ionically conductive polymer having a number averagemolecular weight of at least 100 kg/mol, wherein the ionicallyconductive amorphous inorganic material constitutes at least 40% byweight of the solid-state composition, the first component constitutesat least 10% by weight of the solid-state composition, and the binderconstitutes between 0.5% and 5% by weight of the solid-statecomposition.

In some embodiments, the solid-state composition has an ionicconductivity of at least 1×10−4 S·cm−1. In some embodiments, thesolid-state composition does not include an added salt. In someembodiments, the first component is a polyalkyl, polyaromatic, orpolysiloxane polymer having end groups selected from cyano, thiol,amide, amino, sulfonic acid, epoxy, carboxyl, or hydroxyl groups.Examples of first components include polydimethylsiloxane (PDMS),polybutadiene (PBD), and polystyrene. In some embodiments, the firstcomponent is a cyclic olefin polymer. In some embodiments, the numberaverage molecular weight of the first component ranges from about 500g/mol to 40,000 g/mol, or from 500 g/mol to 25,000 g/mol. In someembodiments, the binder includes styrene. For example, the binder may bestyrene-ethylene butylene-styrene (SEBS).

In some embodiments, particles of the ionically conductive amorphousinorganic material are dispersed in a matrix of an organic phasecomprising the first component and the binder. In some embodiments, thesolid-state composition is an electrolyte. In some embodiments, theionically conductive amorphous inorganic material constitutes at least65% by weight of the solid-state composition, the first componentconstitutes at least 10% by weight of the solid-state composition, andthe binder constitutes between 0.5% and 5% by weight of the solid-statecomposition. In some embodiments, the ionically conductive amorphousinorganic material constitutes at least 80% by weight of the solid-statecomposition, with the balance being the first component and the binder.In some embodiments, the ionically conductive amorphous inorganicmaterial constitutes at least 85% by weight of the solid-statecomposition, with the balance being the first component and the binder.

In some embodiments, the first component has a glass transitiontemperature (Tg) of less than −50° C. In some embodiments, the binderhas a glass transition temperature (Tg) greater than 70° C. In someembodiments, the first component has a glass transition temperature (Tg)of less than −50° C. and the binder has a glass transition temperature(Tg) greater than 70° C. In some embodiments, the ionically conductiveamorphous inorganic material, the first component, and the bindertogether constitute at least 90% of the solid-state composition byweight. In some embodiments, the ionically conductive amorphousinorganic material, the first component, and the binder togetherconstitute at least 99% of the solid-state composition by weight. Insome embodiments, the solid-state composition is a film having athickness of no more than 250 microns. In some embodiments, thesolid-state composition does not solvate polysulfides.

Another aspect of the invention relates to a battery including an anode;a cathode; and a solid-state electrolyte composition as described hereinoperatively associated with the anode and cathode. In some embodiments,the solid-state electrolyte composition includes (a) an ionicallyconductive amorphous inorganic material; (b) a first component, whereinthe first component is a non-ionically conductive polymer having anumber average molecular weight of between 500 g/mol and 50,000 g/mol;and (c) a binder, wherein the binder is a non-ion conducting polymerhaving a number average molecular weight of at least 100 kg/mol, whereinthe ionically conductive amorphous inorganic material constitutes atleast 40% by weight of the solid-state composition, the first componentconstitutes at least 10% by weight of the solid-state electrolytecomposition, and the binder constitutes between 0.5% and 5% by weight ofthe solid-state electrolyte composition.

In some embodiments, the solid-state electrolyte composition has anionic conductivity of at least 1×10−4 S·cm−1. In some embodiments, thesolid-state electrolyte composition does not include an added salt.

In some embodiments, the first component is a linear polymer having endgroups selected from cyano, thiol, amide, amino, sulfonic acid, epoxy,carboxyl, or hydroxyl groups. In some embodiments, the first componentis a polyalkyl, polyaromatic, or polysiloxane polymer having end groupsselected from cyano, thiol, amide, amino, sulfonic acid, epoxy,carboxyl, or hydroxyl groups. Examples of first components includepolydimethylsiloxane (PDMS), polybutadiene (PBD), and polystyrene. Insome embodiments, the first component is a cyclic olefin polymer. Insome embodiments, the number average molecular weight of the firstcomponent ranges from about 500 g/mol to 40,000 g/mol, or from 500 g/molto 25,000 g/mol.

In some embodiments, the binder includes styrene. For example, thebinder may be styrene-ethylene butylene-styrene (SEBS). In someembodiments, particles of the ionically conductive amorphous inorganicmaterial are dispersed in a matrix of an organic phase comprising thefirst component and the binder. In some embodiments, the first componenthas a glass transition temperature (Tg) of less than −50° C. In someembodiments, the binder has a glass transition temperature (Tg) greaterthan 70oC. In some embodiments, the first component has a glasstransition temperature (Tg) of less than −50° C. and the binder has aglass transition temperature (Tg) greater than 70° C. In someembodiments, the ionically conductive amorphous inorganic material, thefirst component, and the binder together constitute at least 90% of thesolid-state composition by weight.

In some embodiments, the ionically conductive amorphous inorganicmaterial, the first component, and the binder together constitute atleast 99% of the solid-state electrolyte composition by weight. In someembodiments, the solid-state electrolyte composition is a film having athickness of no more than 250 microns. In some embodiments, thesolid-state electrolyte composition does not solvate polysulfides.

Another aspect of the invention is a solid-state electrode for use in analkali ion or alkali metal battery. The solid-state electrode includesan inorganic phase comprising an ionically conductive amorphousinorganic material, an electrochemically active material, and anelectronically conductive additive; and an organic phase comprising afirst component and a binder, wherein the first component is anon-ionically conductive polymer having a number average molecularweight of between 500 g/mol and 50,000 g/mol and the binder is a non-ionconducting polymer having a number average molecular weight of at least100 kg/mol.

In some embodiments, the ionically conductive amorphous inorganicmaterial constitutes between 15% and 60% by weight of the inorganicphase, the electrochemically active material constitutes between 30% and80% by weight of the inorganic phase, and the electronically conductiveadditive constitutes between 5% and 25% of the inorganic phase. In someembodiments, the ionically conductive amorphous inorganic materialconstitutes between 30% and 50% by weight of the inorganic phase. Insome embodiments, the electrochemically active material constitutesbetween 30% and 50% by weight of the inorganic phase. In someembodiments, the electronically conductive additive constitutes between10% and 20% of the inorganic phase. In some embodiments, the ionicallyconductive amorphous inorganic material constitutes between 30% and 50%by weight of the inorganic phase and the electrochemically activematerial constitutes between 30% and 50% by weight of the inorganicphase.

In some embodiments, the first component constitutes between 50% and 99%by weight of the organic phase, and the binder constitutes between 1%and 50% by weight of the organic phase. In some embodiments, the firstcomponent constitutes between 95% and 99% by weight of the organicphase, and the binder constitutes between 1% and 5% by weight of theorganic phase.

In some embodiments, the first component is a linear polymer having endgroups selected from cyano, thiol, amide, amino, sulfonic acid, epoxy,carboxyl, or hydroxyl groups. In some embodiments, the first componentis a polyalkyl, polyaromatic, or polysiloxane polymer having end groupsselected from cyano, thiol, amide, amino, sulfonic acid, epoxy,carboxyl, or hydroxyl groups. Examples of first components includepolydimethylsiloxane (PDMS), polybutadiene (PBD), and polystyrene. Insome embodiments, the first component is a cyclic olefin polymer. Insome embodiments, the number average molecular weight of the polymerranges from about 500 g/mol to 40,000 g/mol, or from 500 g/mol to 25,000g/mol.

In some embodiments, the binder includes styrene. For example, thebinder may be styrene-ethylene butylene-styrene (SEBS). In someembodiments, particles of the inorganic phase are dispersed in a matrixof the organic phase.

In some embodiments, the first component has a glass transitiontemperature (Tg) of less than −50° C. In some embodiments, the binderhas a glass transition temperature (Tg) greater than 70° C. In someembodiments, the first component has a glass transition temperature (Tg)of less than −50° C. and the binder has a glass transition temperature(Tg) greater than 70° C.

In some embodiments, the inorganic phase constitutes at least 85% byweight of the solid-state electrode. In some embodiments, the organicphase constitutes between 3% and 15% by weight of the solid-stateelectrode.

In some embodiments, the electrochemically active material is selectedfrom the group consisting of lithium cobalt oxide (LCO), lithiummanganese oxide (LMO), lithium nickel cobalt aluminum oxide (NCA),lithium iron phosphate (LFP) and lithium nickel cobalt manganese oxide(NCM).

In some embodiments, the electrochemically active material is selectedfrom the group consisting of a carbon-containing material, asilicon-containing material, a tin-containing material, lithium, or alithium alloyed metal.

In some embodiments, the solid-state electrode is in contact with asolid-state electrolyte that includes a second inorganic phase and asecond organic phase, the second inorganic phase including an ionicallyconductive amorphous inorganic material and the second organic phaseincluding an electrolyte first component, wherein the electrolyte firstcomponent is a non-ionically conductive polymer having a number averagemolecular weight of between 500 g/mol and 50,000 g/mol and anelectrolyte binder, wherein the electrolyte binder is a non-ionconducting polymer having a number average molecular weight of at least100 kg/mol.

Another aspect of the invention relates to a battery including an anode;a cathode; and an electrolyte composition as described hereinoperatively associated with the anode and cathode. In some embodiments,the anode comprises (a) an inorganic phase comprising an ionicallyconductive amorphous inorganic material, an electrochemically activematerial, and an electronically conductive additive; and (b) an organicphase comprising a first component and a binder, wherein the firstcomponent is a non-ionically conductive polymer having a number averagemolecular weight of between 500 g/mol and 50,000 g/mol and the binder isa non-ion conducting polymer having a number average molecular weight ofat least 100 kg/mol.

In some embodiments, the cathode comprises (a) an inorganic phasecomprising an ionically conductive amorphous inorganic material, anelectrochemically active material, and an electronically conductiveadditive; and (b) an organic phase comprising a first component and abinder, wherein the first component is a non-ionically conductivepolymer having a number average molecular weight of between 500 g/moland 50,000 g/mol and the binder is a non-ion conducting polymer having anumber average molecular weight of at least 100 kg/mol.

In some embodiments, the ionically conductive amorphous inorganicmaterial constitutes between 15% and 60% by weight of the inorganicphase, the electrochemically active material constitutes between 30% and80% by weight of the inorganic phase, and the electronically conductiveadditive constitutes between 5% and 25% of the inorganic phase.

In some embodiments, the first component constitutes between 50% and 99%by weight of the organic phase, and the binder constitutes between 1%and 50% by weight of the organic phase.

In some embodiments, the first component is a linear polymer having endgroups selected from cyano, thiol, amide, amino, sulfonic acid, epoxy,carboxyl, or hydroxyl groups. In some embodiments, the first componentis a polyalkyl, polyaromatic, or polysiloxane polymer having end groupsselected from cyano, thiol, amide, amino, sulfonic acid, epoxy,carboxyl, or hydroxyl groups. Examples of first components includepolydimethylsiloxane (PDMS), polybutadiene (PBD), and polystyrene. Insome embodiments, the first component is a cyclic olefin polymer.

In some embodiments, the binder includes styrene. For example, thebinder may be styrene-ethylene butylene-styrene (SEBS). In someembodiments, particles of the inorganic phase are dispersed in a matrixof the organic phase.

In some embodiments, the first component has a glass transitiontemperature (Tg) of less than −50° C. In some embodiments, the binderhas a glass transition temperature (Tg) greater than 70° C. In someembodiments, the first component has a glass transition temperature (Tg)of less than −50° C. and the binder has a glass transition temperature(Tg) greater than 70° C.

In some embodiments, the inorganic phase constitutes at least 85% byweight of the solid-state electrode. In some embodiments, the organicphase constitutes between 3% and 15% by weight of the solid-stateelectrode.

In some embodiments, the electrochemically active material is selectedfrom the group consisting of lithium cobalt oxide (LCO), lithiummanganese oxide (LMO), lithium nickel cobalt aluminum oxide (NCA),lithium iron phosphate (LFP) and lithium nickel cobalt manganese oxide(NCM). In some embodiments, the electrochemically active material isselected from the group consisting of a carbon-containing material, asilicon-containing material, a tin-containing material, lithium, or alithium alloyed metal.

Another aspect of the invention relates to a method of forming asolid-state composite. The method includes mixing ionically conductiveamorphous inorganic particles with one or more organic components toform a composite, wherein the one or more organic components comprises afirst component and applying external pressure to the composite, whereinapplying external pressure increases the ionic conductivity of thecomposite by a factor of at least two.

In some embodiments, the first component is a polymer having a numberaverage molecular weight of between 500 g/mol and 50,000 g/mol. In someembodiments, the first component is a non-ionically conductive polymer.

In some embodiments, the method further includes releasing the appliedpressure. In some embodiments, the further includes heating thecomposite during the application of pressure to a temperature greaterthan 70° C., and cooling the composite after heating. In someembodiments, an increase of at least a factor of two in ionicconductivity is maintained after releasing the applied pressure. In someembodiments, the one or more organic components further include abinder, wherein the binder is a non-ion conducting polymer having anumber average molecular weight of at least 100 kg/mol.

In some embodiments, the binder has a glass transition temperature (Tg)greater than 21° C. In some embodiments, the binder has a glasstransition temperature (Tg) greater than 70° C. In some embodiments, themethod further includes heating the composite during the application ofpressure to a temperature greater than the Tg of the binder, and coolingthe composite after heating.

In some embodiments, the method further includes releasing the appliedpressure wherein an increase of at least a factor of two in ionicconductivity is maintained after releasing the applied pressure.

In some embodiments, mixing the ionically conductive amorphous inorganicmaterial with the one or more organic components involves solvent-freemechanical mixing. In some embodiments, the method involves dissolvingthe one or more organic components in a solvent and forming a slurrythat comprises the dissolved organic components and the ionicallyconductive amorphous inorganic material. In some embodiments, the methodinvolves casting the slurry on a substrate and evaporating the solvent.In some embodiments, the method involves extruding the composite.

In some embodiments, the ionically conductive amorphous inorganicmaterial constitutes at least 40% by weight of the solid-statecomposition and the first component constitutes at least 10% by weightof the solid-state composition.

In some embodiments, the one or more organic components further includea binder, wherein the binder is a non-ion conducting polymer having anumber average molecular weight of at least 100 kg/mol, and the binderconstitutes between 0.5% and 5% of the composite by weight.

In some embodiments, the method involves mixing an electrochemicallyactive material and an electronically conductive additive with the oneor more organic components.

In some embodiments, the first component is a linear polymer having endgroups selected from cyano, thiol, amide, amino, sulfonic acid, epoxy,carboxyl, or hydroxyl groups. In some embodiments, the first componentis a polyalkyl, polyaromatic, or polysiloxane polymer having end groupsselected from cyano, thiol, amide, amino, sulfonic acid, epoxy,carboxyl, or hydroxyl groups. Examples of first components includepolydimethylsiloxane (PDMS), polybutadiene (PBD), and polystyrene. Insome embodiments, the first component is a cyclic olefin polymer. Insome embodiments, the first component has a glass transition temperature(Tg) of less than −50° C.

Another aspect of the invention relates to a solid-stateelectrode/electrolyte bilayer including an electrode layer having afirst inorganic phase and first organic phase, the first inorganic phaseincluding an ionically conductive amorphous inorganic material, anelectrochemically active material, and an electronically conductiveadditive and the first organic phase including an electrode firstcomponent and an electrode binder, wherein the electrode first componentis a non-ionically conductive polymer having a number average molecularweight of between 500 g/mol and 50,000 g/mol and the electrode binder isa non-ion conducting polymer having a number average molecular weight ofat least 100 kg/mol; and an electrolyte layer disposed on the electrodelayer and having a second inorganic phase and a second organic phase,the second inorganic phase including an ionically conductive amorphousinorganic material and the second organic phase including an electrolytefirst component, wherein the electrolyte first component is anon-ionically conductive polymer having a number average molecularweight of between 500 g/mol and 50,000 g/mol; and an electrolyte binder,wherein the electrolyte binder is a non-ion conducting polymer having anumber average molecular weight of at least 100 kg/mol.

Another aspect of the invention relates to a solid-state compositionincluding an ionically conductive inorganic material; and a firstcomponent, wherein the first component is a polymer having a numberaverage molecular weight of less than 100 kg/mol, wherein the ionicallyconductive amorphous inorganic material constitutes at least 40% byweight of the solid-state composition, the first component constitutesat least 10% by weight of the solid-state composition, and thesolid-state composition has an ionic conductivity of at least 1×10⁻⁴S·cm⁻¹ in the absence of a salt.

In some embodiments, ionically conductive inorganic material isamorphous. In some embodiments, the ionically conductive inorganicmaterial is semi-crystalline or crystalline. In some embodiments, thesolid-state composition further comprises a binder, wherein the binderis a polymer having a number average molecular weight of at least 100kg/mol. In some embodiments, the binder constitutes between 0.5% and 5%by weight of the solid-state composition. In some embodiments, thepolymer is a non-ionically conductive polymer.

In some such embodiments, the first component is polydimethylsiloxane(PDMS), polybutadiene (PBD), or polystyrene. In some embodiments, thefirst component is a cyclic olefin polymer. In some embodiments, thefirst component is a polyalkyl, polyaromatic, or polysiloxane polymerhaving end groups selected from cyano, thiol, amide, amino, sulfonicacid, epoxy, carboxyl, or hydroxyl groups. In some embodiments, thepolymer is an ionically conductive polymer. In some such embodiments,the polymer is a perfluoropolyether (PFPE). In some embodiments, thefirst component has a glass transition temperature (Tg) of less than−50oC. In some embodiments, the binder has a glass transitiontemperature greater than 70oC. In some embodiments, the first componenthas a glass transition temperature (Tg) of less than −50oC and thebinder has a glass transition temperature greater than 70oC.

Another aspect of the invention relates to solid-state compositionincluding an ionically conductive inorganic material; and a firstcomponent, wherein the first component is a non-ionically conductivepolymer having a number average molecular weight of less than 100kg/mol; and wherein the ionically conductive amorphous inorganicmaterial constitutes at least 40% by weight of the solid-statecomposition, the first component constitutes at least 10% by weight ofthe solid-state composition.

In some embodiments, the solid-state composition further comprises abinder, wherein the binder is a non-ionically conductive polymer havinga number average molecular weight of at least 100 kg/mol. In someembodiments, the binder constitutes between 0.5% and 5% by weight of thesolid-state composition.

Another aspect of the invention relates to a solid-state composition,comprising: a composite comprising ionically conductive inorganicparticles and an organic first component, wherein the first component ischaracterized in that it results in at least a 10× increase in ionicconductivity of the composite upon application of an external pressureof at least 10 atm to the composite as compared to a baseline externalpressure of 1 atm, and wherein the first component is non-ionicallyconductive.

In some embodiments, the ionically conductive inorganic particles areamorphous. In some embodiments, the ionically conductive inorganicparticles are semi-crystalline or crystalline. In some embodiments, thesolid-state composition further comprises a binder, wherein the binderis a polymer having a number average molecular weight of at least 100kg/mol. In some embodiments, the binder constitutes between 0.5% and 5%by weight of the solid-state composition. In some embodiments, thebinder has a glass transition temperature greater than 70oC. In somesuch embodiments, the first component is polydimethylsiloxane (PDMS),polybutadiene (PBD), or polystyrene.

In some embodiments, the first component is a cyclic olefin polymer. Insome embodiments, the first component is a polyalkyl, polyaromatic, orpolysiloxane polymer having end groups selected from cyano, thiol,amide, amino, sulfonic acid, epoxy, carboxyl, or hydroxyl groups. Insome embodiments, the first component has a glass transition temperature(Tg) of less than −50oC.

Another aspect of the invention relates to a solid-state compositionincluding composite comprising ionically conductive inorganic particlesand a first component, wherein the first component is an alkane havingbetween 12 and 40 carbons and wherein the weight percentage of the firstcomponent in the composite is between 2.5% and 60%. In some embodiments,the ionically conductive inorganic particles are amorphous. In someembodiments, the ionically conductive inorganic particles aresemi-crystalline or crystalline. In some embodiments, the solid-statecomposition further comprises a binder, wherein the binder is a polymerhaving a number average molecular weight of at least 100 kg/mol.

Another aspect of the invention relates to a solid-state compositionincluding a composite of ionically conductive inorganic particles and afirst component, wherein the first component is a cyclic olefin polymeror a cyclic olefin copolymer and wherein the weight percentage of thefirst component in the composite is between 2.5% and 60%.

These and other aspects of the invention are described further belowwith reference to the Figures.

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1 shows a scanning electron microscope (SEM) image of a pressedpellet of a solid-state composition according to certain embodiments ofthe present invention.

FIG. 2 shows conductivity of a solid-state composition according tocertain embodiments of the present invention as a function of appliedpressure.

FIG. 3 shows a Nyquist plot of electrochemical impedance (EIS) spectraof a full cell including a glass cathode and pelletized compositesolid-state electrolyte according to certain embodiments of the presentinvention with and without pressure applied.

FIG. 4 shows a Nyquist plot of EIS spectra of a full cell including asolid-state composite cathode and pelletized solid-state compositeelectrolyte according to certain embodiments of the present inventionwith and without pressure applied.

FIG. 5 shows a Nyquist plot of EIS spectra of a full cell including asolid-state composite cathode and pelletized solid-state compositeelectrolyte according to certain embodiments of the present inventionwith and without pressure applied.

FIG. 6 is a plot of conductivity of a heat-processed solid-statecomposite electrolyte film according to certain embodiments of thepresent invention as a function of temperature in a pouch cell with noapplied pressure.

FIG. 7 shows an image of a composite cathode/electrolyte bilayeraccording to certain embodiments of the present invention.

FIGS. 8 and 9 show cycling data for Li—In|Composite Electrolyte|Sulfurcells according to certain embodiments of the present invention at threedifferent temperatures (40° C., 25° C., and 0°). FIG. 8 shows dischargecapacity and FIG. 9 shows columbic efficiency.

FIG. 10 shows a voltage profile of a solid-state sulfur cathode in aLi—In|Composite Electrolyte|Sulfur cell according to certain embodimentsof the present invention at C/5 and C/20 discharge rates.

FIG. 11 shows an EIS spectrum of a Li—In|Composite Electrolyte|Sulfurcell according to certain embodiments of the present invention.

FIGS. 12-14 show examples of schematics of cells according to certainembodiments of the present invention.

DETAILED DESCRIPTION

One aspect of the present invention relates to ionically conductivesolid-state compositions that include ionically conductive inorganicparticles in a matrix of an organic material. The resulting compositematerial has high ionic conductivity and mechanical properties thatfacilitate processing. In particular embodiments, the ionicallyconductive solid-state compositions are compliant and may be cast asfilms.

Another aspect of the present invention relates to batteries thatinclude the ionically conductive solid-state compositions describedherein. In some embodiments of the present invention, solid-stateelectrolytes including the ionically conductive solid-state compositionsare provided. In some embodiments of the present invention, electrodesincluding the ionically conductive solid-state compositions areprovided.

Particular embodiments of the subject matter described herein may havethe following advantages. In some embodiments, the ionically conductivesolid-state compositions may be processed to a variety of shapes witheasily scaled-up manufacturing techniques. The manufactured compositesare compliant, allowing good adhesion to other components of a batteryor other device. The solid-state compositions have high ionicconductivity, allowing the compositions to be used as electrolytes orelectrode materials. In some embodiments, ionically conductivesolid-state compositions enable the use of lithium metal anodes byresisting dendrites. In some embodiments, the ionically conductivesolid-state compositions do not dissolve polysulfides and enable the useof sulfur cathodes.

Further details of the ionically conductive solid-state compositions,solid-state electrolytes, electrodes, and batteries according toembodiments of the present invention are described below.

The ionically conductive solid-state compositions may be referred to ashybrid compositions herein. The term “hybrid” is used herein to describea composite material including an inorganic phase and an organic phase.The term “composite” is used herein to describe a composite of aninorganic material and an organic material.

In some embodiments of the present invention, the organic materialincludes a first component that, on application of external pressure,facilitates movement of the ionically conductive particles in thecomposite. The first component is liquid or a soft solid at thetemperature at which external pressure is applied to the solid-statecomposition.

In some embodiments, the first component may be characterized as havinga liquid or liquid-like nature at least at the temperature at whichexternal pressure is applied. The combination of pressure and the liquidor liquid-like nature of the first component deliver conductivity valuesclose to the conductivity of the pristine solid-state ionicallyconductive particles. The result is highly conductive, dense, andcompliant material that can be easily processed to desired shapes.Pristine refers to the particles prior to incorporation into thecomposite. According to various embodiments, the material has at leasthalf, at least 80%, or at least 90% of the ionic conductivity of theparticles.

The first component may be any compound that is compatible with thesolid-state ionically conductive particles, is non-volatile, and isnon-reactive to battery components such as electrodes. It may be furthercharacterized by being non-polar or having low-polarity. The firstcomponent may interact with inorganic phase such that the components mixuniformly and microscopically well, but without reactivity between them.Interactions can include one or both of physical or chemicalinteractions. A first component that is non-reactive to the inorganicphase may still form bonds with the surface of the particles, but doesnot degrade or change the composition of the inorganic phase. Examplesof classes of first components include long chain alkanes and polymers.Specific examples of first components are described further below.

As indicated above, the first component is a component that is a liquidor a soft solid at the time when external pressure is applied. In someembodiments, the first component may be a solid at room temperature orother operating temperature and be liquid or liquid-like at an elevatedtemperature, with the external pressure applied at the elevatedtemperature when the first component is in the liquid or liquid-likestate. With this approach, effective particle-to-particle contact can belocked in by applying pressure during the cooling and solidification orhardening of the first component. Particle-to-particle contact andconductivity remains high after pressure is released. In someembodiments, high ionic conductivity can be maintained after pressure isreleased by using an appropriate solid-state high molecular weightpolymer binder in a three-component system, discussed further below. Insome other embodiments, the first component may be liquid or liquid-likeat room temperature or other operating temperature with externalpressure applied. In some such cases, pressure may be maintainedthroughout operation to main high conductivity.

In some embodiments, the solid-state compositions include a small amountof a solid-state high molecular weight polymer binder. Such systems arereferred to as three-component systems, the three components being theionically conductive inorganic particles, the first component, and thesolid-state high molecular weight polymer binder. The presence of thefirst component enables application of a solid-state high molecularweight polymer binder without sacrificing high conductivity. This resultis significant because without the first component, the addition of evena small amount (1-5 wt %) of a solid-state high molecular weight polymerbinder to a solid-state ion conductor can result in a drastic decreasein the conductivity. In some embodiments, the high conductivity of thecomposition is achieved by better mobility of the solid-state particleswhen in a first component, so that effective particle-to-particlecontact can be achieved even when the solid-state high molecular weightpolymer binder is present. The solid-state high molecular weight polymerbinder can facilitate improved mechanical properties. Details of theinorganic phase and organic phase of the compositions are describedbelow.

The term “number average molecular weight” or “M_(n)” in reference to aparticular component (e.g., a first component or high molecular weightpolymer binder) of a solid-state composition refers to the statisticalaverage molecular weight of all molecules of the component expressed inunits of g/mol. The number average molecular weight may be determined bytechniques known in the art such as, for example, gel permeationchromatography (wherein M_(n) can be calculated based on known standardsbased on an online detection system such as a refractive index,ultraviolet, or other detector), viscometry, mass spectrometry, orcolligative methods (e.g., vapor pressure osmometry, end-groupdetermination, or proton NMR). The number average molecular weight isdefined by the equation below,

$M_{n} = \frac{\Sigma N_{i}M_{i}}{\Sigma N_{i}}$wherein M_(i) is the molecular weight of a molecule and N_(i) is thenumber of molecules of that molecular weight.

The term “weight average molecular weight” or “M_(w)” in reference to aparticular component (e.g., a first component or high molecular weightpolymer binder) of a solid-state composition refers to the statisticalaverage molecular weight of all molecules of the component taking intoaccount the weight of each molecule in determining its contribution tothe molecular weight average, expressed in units of g/mol. The higherthe molecular weight of a given molecule, the more that molecule willcontribute to the M_(w) value. The weight average molecular weight maybe calculated by techniques known in the art which are sensitive tomolecular size such as, for example, static light scattering, smallangle neutron scattering, X-ray scattering, and sedimentation velocity.The weight average molecular weight is defined by the equation below,

$M_{w} = \frac{\Sigma N_{i}M_{i}^{2}}{\Sigma N_{i}M_{i}}$wherein ‘M_(i)’ is the molecular weight of a molecule and ‘N_(i)’ is thenumber of molecules of that molecular weight. In the description below,references to molecular weights of particular polymers refer to numberaverage molecular weight.Inorganic Phase

The inorganic phase of the composite materials described herein conductsalkali ions. In some embodiments, it is responsible for all of the ionconductivity of the composite material, providing ionically conductivepathways through the composite material.

In some embodiments, the inorganic phase is a particulate solid-statematerial that conducts alkali ions. In the examples given below, lithiumion conducting materials are chiefly described, though sodium ionconducting or other alkali ion conducting materials may be employed.According to various embodiments, the materials may be glass particles,ceramic particles, or glass ceramic particles. The solid-statecompositions described herein are not limited to a particular type ofcompound but may employ any solid-state inorganic ionically conductiveparticulate material, examples of which are given below.

In some embodiments, the inorganic material is a single ion conductor,which has a transference number close to unity. The transference numberof an ion in an electrolyte is the fraction of total current carried inthe electrolyte for the ion. Single-ion conductors have a transferencenumber close to unity. According to various embodiments, thetransference number of the inorganic phase of the solid electrolyte isat least 0.9 (for example, 0.99).

The inorganic phase may be an oxide-based composition, a sulfide-basedcomposition, or a phosphate-based composition, and may be crystalline,partially crystalline, or amorphous. In certain embodiments, theinorganic phase may be doped to increase conductivity. Examples of solidlithium ion conducting materials include perovskites (e.g.,Li_(3x)La_((2/3)−x)TiO₃, 0≤x≤0.67), lithium super ionic conductor(LISICON) compounds (e.g., Li_(2+2x)Zn_(1−x)GeO₄, 0≤x≤1; Li₁₄ZnGe₄O₁₆),thio-LISICON compounds (e.g., Li_(4−x)A_(1−y)B_(y)S₄, A is Si, Ge or Sn,B is P, Al, Zn, Ga; Li₁₀SnP₂S₁₂), garnets (e.g. Li₇La₃Zr₂O₁₂,Li₅La₃M₂O₁₂, M is Ta or Nb); NASICON-type Li ion conductors (e.g.,Li_(1.3)Al_(0.3)Ti_(1.7)(PO₄)₃), oxide glasses or glass ceramics (e.g.,Li₃BO₃—Li₂SO₄, Li₂O—P₂O₅, Li₂O—SiO₂), sulfide glasses or glass ceramics(e.g., 75Li₂S-25P₂S₅, Li₂S—SiS₂, LiI—Li₂S—B₂S₃) and phosphates (e.g.,Li_(1−x)Al_(x)Ge_(2−x)(PO₄)₃ (LAGP), Li_(1+x)Ti_(2−x)Al_(x)(PO₄)).Further examples include lithium rich anti-perovskite (LiRAP) particles.As described in Zhao and Daement, Jour J. Am. Chem. Soc., 2012, 134(36), pp 15042-15047, incorporated by reference herein, these LiRAPparticles have an ionic conductivity of greater than 10⁻³ S/cm at roomtemperature.

Examples of solid lithium ion conducting materials include sodium superionic conductor (NASICON) compounds (e.g., Na_(1+x)Zr₂Si_(x)P_(3−x)O₁₂,0<x<3). Further examples of solid lithium ion conducting materials maybe found in Cao et al., Front. Energy Res. (2014) 2:25 and Knauth, SolidState Ionics 180 (2009) 911-916, both of which are incorporated byreference herein.

Further examples of ion conducting glasses are disclosed in Ribes etal., J. Non-Cryst. Solids, Vol. 38-39 (1980) 271-276 and Minami, J.Non-Cryst. Solids, Vol. 95-96 (1987) 107-118, which are incorporated byreference herein.

According to various embodiments, an inorganic phase may include one ormore types of inorganic ionically conductive particles. The particlesize of the inorganic phase may vary according to the particularapplication, with an average diameter of the particles of thecomposition being between 0.1 μm and 500 μm for most applications. Insome embodiments, the average diameter is between 0.1 μm and 100 μm. Insome embodiments, a multi-modal size distribution may be used tooptimize particle packing. For example, a bi-modal distribution may beused. In some embodiments, particles having a size of 1 μm or less areused such that the average nearest particle distance in the composite isno more than 1 μm. This can help prevent dendrite growth.

The inorganic phase may be manufactured by any appropriate method. Forexample, crystalline materials may be obtained using different syntheticmethods such as sol-gel and solid state reactions. Glass electrolytesmay be obtained by mechanical milling as described in Tatsumisago, M.;Takano, R.; Tadanaga K.; Hayashi, A. J. Power Sources 2014, 270,603-607, incorporated by reference herein.

In certain embodiments, the inorganic phase is an amorphous glassmaterial rather than a crystalline glass-ceramic material. For certainformulations of the solid-state composition, conductivity issignificantly improved by use of an amorphous glass material. This isbecause crystalline and semi-crystalline ionically conductive particlescan have anisotropic conductive paths, whereas amorphous materials haveisotropic conductive paths. In some embodiments in which crystalline andsemi-crystalline ionically conductive particles are used, sintering maybe used to increase ionic conductivity.

Organic Phase

The organic phase provides materials properties, such as compliance anddensity, that facilitate processing of the composites and their usebatteries. The organic phase includes one or more components that, onapplication of pressure, allow the ionic conductivity of the compositeto increase.

The ionically conductive compositions described herein may include aninorganic particulate phase in a matrix of an organic phase. Accordingto various embodiments, the organic phase may include one or morecomponents. There are several considerations in selecting the one ormore components of the organic phase, including ionic conductivity andmaterial properties of the formed compositions, and material propertiesrelevant to manufacturing.

In many embodiments, the ionic conductivity is supplied entirely by theinorganic phase, with the organic phase being non-ionically conductive.Each of the one or more components of the organic phase may benon-ionically conductive. During processing of the composite, theorganic phase allows inorganic phase particle-to-particle contact to beestablished. The particle-to-particle contacts establish conductivepathways resulting in high ionic conductivity.

The ionically conductive compositions are not brittle and can beprocessed into a variety of shapes. In some embodiments, thecompositions can be densified by application of pressure. Thecompositions have material properties such as density, modulus, andhardness that are sufficient to resist dendrite formation in someembodiments. The organic phase occupies the space between inorganicparticles.

The organic phase of the composition is such that external pressureapplied during processing allows particle-to-particle contact asdescribed above. In some embodiments, the organic phase allows pressureto be released while maintaining the particle-to-particle contact andhigh ionic conductivity.

Described below are “two-component” and “three-component” hybridcompositions. In the two-component composition, the organic phase hasone component, a relatively low molecular weight component referred toas the “first component.” The two-component compositions do not includea high molecular weight polymer binder. In the three-componentcomposition, the organic phase includes the first component and a highmolecular weight polymer binder.

The molecular weight of the first component can vary and depends on thetype of compound. However, it is significantly less than high molecularweight polymer binders, which generally have molecular weights of 100kg/mol and above. The first component may be characterized in thatapplication of external pressure to the composite material results in asignificant increase in ionic conductivity as a result of the firstcomponent. Application of external pressure creates particle-to-particlecontacts and high ion conductivity. According to various embodiments,the ionic conductivity may increase by at least 2×, 4×, or 10× onapplication of at least 10 atm (1.013 MPa) as compared to a baselineapplied pressure of 1 atm. In some embodiments, the ionic conductivitymay increase by at least 2×, 4×, or 10× on application of at least 10MPa as compared to a baseline applied pressure of 1 atm (1.013 MPa). Thecomposite may have an ionic conductivity of at least 1×10⁻⁴ S·cm¹.

In some embodiments, the first component is a material that is a liquidor behaves as a liquid or similarly to a liquid at one or both of themanufacturing temperature and operating temperature of the compositionor battery that includes the composition. The term “behaving as a liquidor similarly to a liquid” means that the first component that allows theparticles of the inorganic phase to move easily in the composition onapplication of pressure. In some embodiments, the first component may bea soft solid that allows the particles of the inorganic phase to move onapplication of pressure. The first component may be characterized orreferred to as a “molecular grease” or “lubricating component,” thoughthese terms are not intended to limit the first component to anyparticle class of compounds.

The presence of the first component in a relatively high amount (2.5-60wt % of the solid-state composite electrolyte) can provide a materialhaving desirable mechanical properties. According to variousembodiments, the material is soft and can be processed to a variety ofshapes. In addition, the first component fills voids in the material,resulting in a dense material.

The first component is non-volatile and is compatible with the inorganicphase. Compatibility with the inorganic phase means that the firstcomponent interacts with the inorganic phase so that the components mixuniformly and microscopically well, but without reactivity between them.As discussed further below, certain first components may befunctionalized for surface interactions with the inorganic phase,however, the first component does not otherwise react or degrade withthe inorganic phase. Surface interactions can include covalent bonds,ionic bonds, van der Waals forces, and hydrogen bonds. In someembodiments, surface interactions, if present, are weak at least at thetemperature pressure is applied to allow the particles to move easily inthe composite.

As indicated above, the first component allows particles of theinorganic phase to move around easily on application of pressure at atemperature or range of temperatures, Tp, at which pressure is to beapplied. As such, the first component may be any compatible materialthat, when in a composite with ionically conductive particles, shows anorder of magnitude difference in conductivity on application of externalpressure. Applied pressure may be 1-200 MPa according to variousembodiments. Examples 5 and 6, below, demonstrate the effect of pressureon ionic conductivity.

Examples of first components are provided below. According to variousembodiments, the first component may be characterized according to oneor more of the following: glass transition temperature, meltingtemperature, or viscosity.

In some embodiments, the first component may be a relatively smallmolecular weight polymer material. The size of the polymer phase mayvary, though as noted above, it is significantly less than 100 kg/mol.Examples of sizes range from about 500 g/mol to about 50,000 g/mol.Under applied pressure, a relatively small molecular weight material isable to flow, where a larger material cannot. In some embodiments, thesize of the polymer ranges from about 500 g/mol to 40,000 g/mol, or from500 g/mol to 25,000 g/mol.

Examples of polymeric first components include polymers that have a lowglass transition temperature (Tg). According to various embodiments, thepolymers have glass transition temperatures of less than about −50° C.,less than about −70° C., less than about −90° C., or lower. In someembodiments, a polymeric first component is an elastomer. Examples ofpolymers include PDMS (Tg of −125° C.) and polybutadiene (PBD) (Tg of−90° C. to −111° C.). Glass transition temperatures as provided hereinare examples and may vary depending on the size, particular compositionand/or isomeric form of the polymer. For example, the glass transitiontemperature of PBD depends on the degree of cis, trans, or vinylpolymerization. Particular PBDs include liquid polybutadienes withhydroxyl functional groups and hydrogenated liquid polybutadienes withhydroxyl functional groups. Polymeric first components may behomopolymers or copolymers. For example, random copolymers such asstyrene butadiene rubbers (SBR) (Tg of −55° C.), ethylene propylenerubbers (EPRs) (Tg of −60° C.), and isobutylene isoprene rubbers (IIR)(Tg of −69° C.) may be used.

Crystalline polymeric first components may also be characterized interms of melting temperature Tm. Crystalline polymeric first componentsmay have a melting temperature less than about room temperature in someembodiments. In some embodiments, if the composite is heat processed (asdescribed below), the melting temperature may be higher, e.g., less than150° C., less than 100° C., or less than 50° C. For example, PDMS (Tm of−40° C.) may be preferred in some embodiments over polyethylene (PE; Tmof 120° C. to 180° C.) as the former is liquid at lower temperatures.Glass transition temperatures as provided herein are examples and mayvary depending on the size, particular composition and/or isomeric formof the polymer. Melting temperatures of PBD, for example, varysignificantly on the degree of cis, trans, or vinyl polymerization.

In some embodiments, the organic phase is substantially non-ionicallyconductive, with examples of non-ionically conductive polymers includingPDMS, PBD, and the other polymers described above. Unlike ionicallyconductive polymers such as polyethylene oxide (PEO), polypropyleneoxide (PPO), polyacrylonitrile (PAN), poly(methyl methacrylate) (PMMA),which are ionically conductive because they dissolve or dissociate saltssuch as LiI, non-ionically conductive polymers are not ionicallyconductive even in the presence of a salt. This is because withoutdissolving a salt, there are no mobile ions to conduct.

Another class of polymers that may be used are perfluoropolyethers(PFPEs) as described in Compliant glass-polymer hybrid singleion-conducting electrolytes for lithium ion batteries, PNAS, 52-57, vol.113, no. 1 (2016), incorporated by reference herein. As describedtherein, PFPEs are ionically conductive, being single ion-conductors forlithium.

In some embodiments, a polymeric first component may be a thermoplasticpolymer with a Tg greater than room temperature. Examples include cyclicolefin polymers (COPs), cyclic olefin copolymers (COCs), and polystyrene(PSt; Tg of 100° C.). The glass transition temperature or meltingtemperature of a COP or COC can vary widely. COPs, COCs, and PSt areexamples of thermoplastic polymers that may be used with the heatprocessing manufacturing methods described further below. In someembodiments, a thermoplastic polymer having a Tg or Tm greater than 70°C. is used.

In many embodiments, the first component is a linear compound, such alinear polymer or long-chain alkane, though branched compounds may alsobe used in some embodiments. The main chain, or backbone, of the firstcomponent is selected such that it does not interact with inorganicphase or coordinate with lithium ions or other alkali ions. Examples ofbackbones that may be used include saturated or unsaturated polyalkyls,polyaromatics, and polysiloxanes. Examples of backbones that mayinteract too strongly with the inorganic phase include those with strongelectron donating groups such as polyalcohols, polyacids, polyesters,polyethers, polyamines, and polyamides. It is understood that moleculesthat have other moieties that decrease the binding strength of oxygen orother nucleophile groups may be used. For example, the perfluorinatedcharacter of the PFPE backbone delocalize the electron density of theether oxygens, and allow them to be used as first components. Ifbranched, the branches of the first component may either notfunctionalized or be functionalized with groups (such as methyl groups)that do not interact with the inorganic phase.

According to various embodiments, the end groups of the first componentmay or may not be tailored to interact with the particles of theinorganic phase. In some embodiments, the end groups of a polymer aretailored for interaction with the inorganic phase. For example, in someembodiments, the end group is one that can bond, via a covalent bond, anionic bond, or a hydrogen bond, to the particles of the inorganic phase.Examples of end groups include cyano, thiol, amide, amino, sulfonicacid, epoxy, carboxyl, or hydroxyl groups. The two end groups of aparticular polymer may be the same or different. In some embodiments, amixture of polymers having different end groups may be used. Theinteraction of the polymer phase to the inorganic particles, asdetermined by the polymer end groups, can be tailored to obtain atexture suitable for a compliant electrolyte having high ionicconductivity. In such embodiments, the polymer is small enough that theconcentration of the end group is high enough to achieve the desiredinteraction and texture. Examples of sizes range from 500 g/mol to25,000 g/mol, and depend on the particular polymer used. In someembodiments, the size may be between 500 g/mol to 15,000 g/mol, 500g/mol to 10,000 g/mol or 500 g/mol to 5000 g/mol.

In some embodiments, the first component is a long-chain alkane(C_(n)H_(2n+2)). In particular, paraffin oils and waxes may be used.Paraffin waxes are mixtures of long-chain alkanes C_(n)H_(2n+2) having nbetween 20 and 40. Paraffin oils are smaller, having fewer than twentycarbons. While smaller paraffin oils may be too volatile, largerparaffin oils (e.g., n=17) may be suitable for use. Branched alkanes mayalso be used. For example, a paraffin wax may be modified by theaddition of one or branches off the long-chain alkanes a mixture.Example melting points for paraffin wax are between about 46° C. and 68°C. Paraffin oils are liquid at room temperature.

In some embodiments, the first component is a non-polar or low-polarcomponent. In some embodiments, non-polar components are characterizedby having a dielectric constant of less than 3 at all frequencies andlow-polar components are characterized by having a dielectric constantbetween 3 and 5 at low frequency (60 Hz) and room temperature. In thedescription herein, polarity of a functionalized polymer component isdetermined by its backbone. For example, a non-polar first component mayhave a non-polar linear polydimethylsiloxane (PDMS) backbone that isfunctionalized with polar end groups. On application of externalpressure, the ionic conductivity of the composite is significantlyincreased. Highly polar polymers such as polyvinylidenefluoride (PVDF)are not effective first components as they may interact too stronglywith the inorganic phase.

The temperature or range of temperatures Tp at which pressure is to beapplied may vary. In some embodiments, pressure may be constantlyapplied during use with the first component exhibiting liquid orliquid-like characteristics over the range of operating temperatures.Example operating temperatures ranges are from −20° C. to 100° C., or−10° C. to 60° C., 0° C. to 60° C.

In some embodiments, Tp is greater than the operating temperature range.As discussed further below, in some embodiments the compositionincludes, along with the inorganic phase and the first component, a highmolecular weight polymer binder that allows pressure to be releasedwithout losing high ionic conductivity.

In some embodiments, a first component may be chosen such that it isresponsive to pressure only at temperatures greater than operatingtemperatures. Pressure may be applied during manufacturing to establishcontact between the particles of the inorganic phase. Once the compositeis cooled, pressure may be released with the first component solidifiedor hardened and the particles set in place. For example, a COP having amelting temperature of 70° C., above an operating temperature, may beemployed. External pressure is applied at a temperature greater than 70°C. to create good particle-to-particle contact and high ionicconductivity, with the external pressure maintained as the composite iscooled to room temperature. The pressure is then released with the COPsolidified and the particles set in place such that the high ionicconductivity is maintained.

The inorganic phase can put an upper limit on acceptable Tp's. Inparticular, in embodiments in which an amorphous inorganic phase isused, Tp is lower than the temperature at which the inorganic phase willstart to undergo phase transitions or otherwise degrade or change. Forexample, if the inorganic phase starts to crystallize at about 165° C.,a manufacturing temperature may be limited to 140° C. According tovarious embodiments, Tp may range from room temperature (21° C.) to 200°C. or from room temperature to 150° C. Also, as noted above, in someembodiments, Tp is above room temperature. In some such embodiments, Tpmay range from 50° C. to 200° C., 50° C. to 150° C., or 50° C. to 100°C., for example.

For first components that have well-defined melting temperature Tm, thefirst component may be characterized as having a Tm at or below Tp insome embodiments. For example, for crystalline polymers, the firstcomponent may be characterized by its melting temperature Tm. Othertypes of first components, such as paraffins, also may be characterizedby their melting temperatures Tm, as described above. In someembodiments, the first component may be further characterized by havinga melting temperature above room temperature, or above 50° C. It shouldbe noted, however, that in some embodiments, a first component may beone that has a Tm above Tp, but is soft enough to allow particles tomove within the composite under applied pressure.

In some embodiments, a first component is characterized by having ameasurable or reported viscosity at Tp. For example, a first componentmay have a viscosity between 1 and 3,000,000 cp at Tp. (For reference,shortening is reported to have a viscosity of 1,000,000 to 2,000,000cp.) In some embodiments, the first component is fairly viscous, havinga viscosity of at least 2000 cp at Tp. The first component may also becharacterized with references to a viscosity at 25° C. of between 2000cp and 3,000,000 cp. The viscosity of first component may beshear-dependent. For example, it may be a shear-thinning or shearthickening. The first component may be characterized as having aviscosity as measured under no shear stress (e.g., at least 2,000 cp at25° C. or Tp with no applied shear stress).

In some embodiments, the solid-state compositions include a solid-statepolymer binder along with the inorganic phase and the first component.These systems may be referred to as three-component systems. Thepresence of a small amount of a polymer binder can improveprocessability, for example, turning a powdery mixture into a castablethin film.

The polymer binder is a high molecular weight (at least 100 kg/mol)polymer. In some embodiments, the polymer binder has a non-polarbackbone. Examples of non-polar polymer binders include polymers orcopolymers including styrene, butadiene, isoprene, ethylene, andbutylene. Styrenic block copolymers including polystyrene blocks andrubber blocks may be used, with examples of rubber blocks including PBDand polyisoprene. The rubber blocks may or may be hydrogenated. Specificexamples of polymer binders are styrene ethylene butylene styrene(SEBS), styrene-butadiene-styrene (SBS), styrene-isoprene-styrene (SIS),styrene-butadiene rubber (SBR), PSt, PBD, polyethylene (PE), andpolyisoprene (PI).

In some embodiments, the solid-state compositions include a highmolecular weight version of one of the first component described aboveto act as a polymer binder. In such cases, the high molecular weightpolymer is either not functionalized or end groups (such as methyl endgroups) that do not interact with the inorganic phase. For example, asolid-state composition may include 500 kmol/g PDMS with methyl endgroups in addition to a hydroxyl or amino functionalized 900 mol/g (0.9kmol/g) PDMS. As described above, in some embodiments, the firstcomponent and the polymer binder are non-polar polymers. In someembodiments, either of the organic phase components may be characterizedby a lack of electron donating groups on its backbone. For example, itmay be characterized by a lack of any one of ester, ether, amine, amide,or hydroxyl groups on its backbone.

In some embodiments, the high molecular weight polymer binder is athermoplastic that has a glass transition temperature or meltingtemperature greater than operating temperatures. In such cases, pressuremay be applied during manufacturing to establish contact between theparticles of the inorganic phase. Once the composite is cooled, pressuremay be released with the high molecular weight polymer binder solidifiedor hardened and the particles set in place. In some embodiments, thebinder has a glass transition temperature of at least 70° C. Forexample, a high molecular weight polymer binder may be chosen having aglass transition temperature between 70° C. and 140° C. Externalpressure is applied at 140° C. to create good particle-to-particlecontact, and the composite is cooled to room temperature of 21° C. Thepressure is then released with the high molecular weight polymer bindersolidified and the particles set in place. Examples of binders havingTg's greater than room temperature include styrene-containing binderssuch as SEBS. In some embodiments, a thermoplastic binder may be used ina system with a first component that has a low glass transitiontemperature. For example, in some embodiments, a composite includes abinder having a Tg greater than 70° C. and first component having a Tgof less than −50° C.

Composite Materials

The solid-state compositions described herein generally include aninorganic solid phase and a first component as described above. Thecompositions may depend in part on the application, with exampleapplications including solid-state electrolytes and solid-stateelectrodes.

Loading refers to weight percent or volume percent that a componentoccupies in the composition or part thereof. In the description herein,loadings are provided as weight percentages. The first component loadingis large enough that along with the polymer binder, if present, it fillsthe space between the inorganic particles such that there is no orminimal void space in the composition and has desirable mechanicalproperties. If the loading is too high, however, it can reduceconductivity. The total polymer loading in a solid-state composite maybe between 2.5% and 60%, by weight.

According to various embodiments, the first component loading in thecomposition is at least 2.5%, at least 5%, at least 10%, at least 11%,at least 12%, at least 13%, at least 14%, at least 15%, at least 16%, atleast 17%, at least 18%, at least 19%, at least 20%, at least 22%, atleast 24%, at least 26%, at least 28%, or at least 30%, or at least 32%,at least 35% by weight, at least 40%, at least 45%, or at least 50%, ineach case by weight. The total polymer loading in the composite materialdoes not exceed 60%.

As noted above, in some embodiments, the compositions include threecomponents: particles of an inorganic ionic conductor, a firstcomponent, and a high molecular weight solid-state polymer binder. Whilethe total polymer loading in a three-component composition may be asmuch as 60% by weight, the amount of the high molecular weight polymerbinder may be limited to maintain conductivity. According to variousembodiments, the high molecular weight polymer binder is between 0.5%and 10% or between 0.5% and 5% by weight of the material. In someembodiments, the high molecular weight polymer binder is between 0.5%and 4% by weight of the composition, between 0.5% and 3% by weight ofthe composition, between 0.5% and 2.5% by weight of the composition,between 0.5% and 2% by weight of the composition, or between 0.5% and1.5% by weight of the composition.

In some embodiments, the solid-state compositions consist essentially ofinorganic ionically conductive particles and a first component. In someembodiments, the solid-state compositions consist essentially ofionically conductive particles, a first component, and a solid-statehigh molecular weight polymer binder. In some embodiments, thesolid-state composition may include a mixture of different firstcomponents, and or a mixture of different high molecular weight polymerbinders. In such cases, the solid-state composition may consistessentially of inorganic ionically conductive particles and a mixture ofdifferent first components. In some embodiments, the solid-statecomposition may consist essentially of inorganic ionically conductiveparticles, a first component or a mixture of different first components,and a high molecular weight polymer binder or a mixture of highmolecular weight polymer binders.

In alternative embodiments, one or more components other than theinorganic ionically conductive particles, one or more first components,and one or more polymer binders may be added to the solid-statecompositions. According to various embodiments, the solid-statecompositions may or may not include an added salt. Salts such as lithiumsalts (e.g., LiPF₆, LiTFSI), potassium salts, and sodium salts may beadded to improve conductivity. However, in some embodiments, they arenot used with the contacting ionically conductive particles responsiblefor all of the ion conduction. In some embodiments, the solid-statecompositions include substantially no added salts. “Substantially noadded salts” means no more than a trace amount of a salt. In someembodiments, if a salt is present, it does not contribute more than 0.05mS/cm or 0.1 mS/cm to the ionic conductivity. In some embodiments, thesolid-state composition may include one or more conductivity enhancers.In some embodiments, the electrolyte may include one or more fillermaterials, including ceramic fillers such as Al₂O₃. If used, a fillermay or may not be an ion conductor depending on the particularembodiment. In some embodiments, the composite may include one or moredispersants. Further, in some embodiments, an organic phase of asolid-state composition may include one or more additional organiccomponents to facilitate manufacture of an electrolyte having mechanicalproperties desired for a particular application. In some embodiments,discussed further below, the solid-state compositions includeelectrochemically active material.

The solid-state compositions may be prepared by any appropriate methodwith example procedures described below with reference to the Examples.Mixing of the solid-state ionically conductive particles and the firstcomponent to disperse the particles in the first component can beachieved by mechanical means using planetary mixers. The resultingcomposite may have a wide range of textures from clay-like solids topastes depending on the nature of the components and their content. Forexample, the solid-state compositions described herein may have arubbery texture and are not in the form of powder, pebbles, or balls. Insome embodiments, they are not sticky and may be characterized ascohesive rather than adhesive. In some embodiments, the compositionshave a modulus of at least about 9 GPa (about 2.5× the modulus oflithium metal) to prevent the growth of lithium dendrites. Thecomposites prepared by this method may be microscopically dense andcompliant and can be processed to different shapes, for example, intopellets.

Uniform films can also be prepared by solution processing methods. Inthis method, the first component is dissolved in an appropriate solventthat is able to suspend particles of the solid-state on conductorwithout reacting with or otherwise degrading them. A solid-state polymerbinder can also be dissolved at this point to reinforce the finalmaterial. The components are mixed well with the help of homogenizerfollowed by casting the slurry on a selected substrate by a number ofindustrial methods. The solution processing gives porous films aftersolvent evaporation. Densification operations (e.g., by rolling incalender machine) may be applied to densify the layer and improve itsadhesion to the substrate. In embodiments in which solution processingmethods are used, the first component and the polymer binder are solublein a non-polar solvent. Insoluble polymers such as polyphenylene sulfide(PPS) and polytetrafluoroethylene (PTFE) may not be used.

Examples of methods of producing a composite material by ball-millingare described in Examples 1 and 2. Examples of methods of producing acomposite material by solvent casting are described in Example 2. Insome embodiments, the ionically conductive films are prepared byextrusion.

External pressure, e.g., on the order of 1 MPa to 200 MPa, or 1 MPa to100 MPa, is applied to establish high conductivity. The preparedcomposite (e.g., as a pellet or a thin film) is incorporated to anactual solid-state lithium battery by well-established methods.Continuous external pressure is applied to the assembled battery withthe help of screws, springs, clamps, etc. depending on the cell format.

In some embodiments, the solid-state composition is prepared by heatprocessing, with the pressure applied at a temperature above operatingtemperature. For example, when the first component is solid or hardenedat room temperature or other normal operation temperature, the compositematerial may be subjected to a heat-cool cycle while pressure ismaintained. Similarly, when a high molecular weight polymer binderhaving a glass transition temperature above the operating temperature isused, the composite material may be subjected to a heat-cool cycle whilepressure is maintained. Once cooled, the pressure can be decreased orreleased completely. An example of preparing a composite material byheat processing is provided in Example 6.

Electrolytes

In one aspect of the invention, solid-state composite electrolytes areprovided. The solid-state composite electrolytes may be two-componentcompositions or three-component compositions described above. Theelectrolyte may be formed directly on a functional substrate, such as anelectrode, or formed on a removable substrate that is removed beforeassembling the solid-state electrolyte to other components of a battery.

In some embodiments, two-component solid-state composite electrolytesconsisting essentially of a first component and the ionically conductiveinorganic particles as described above are provided. In someembodiments, three-component solid-state composite electrolytesconsisting essentially of a first component, a high molecular weightpolymer binder, and ionically conductive inorganic particles asdescribed above are provided. However, there may be other components ofthe electrolytes as described above. In some such embodiments, the firstcomponent, high molecular weight polymer binder (if present), andionically conductive inorganic particles constitute at least 90% byweight of the solid-state composite electrolyte, and, in someembodiments, at least 95% by weight of the solid-state compositeelectrolyte.

In some embodiments, ionically conductive amorphous inorganic particlesconstitutes at least 60% by weight of the solid-state electrolyte. Insome such embodiments, the balance of the solid-state electrolyte is thefirst component and the binder. In some embodiments, ionicallyconductive amorphous inorganic particles constitutes at least 80% byweight of the solid-state electrolyte. In some such embodiments, thebalance of the solid-state electrolyte is the first component and thebinder. In some embodiments, ionically conductive amorphous inorganicparticles constitutes at least 85% by weight of the solid-stateelectrolyte. In some such embodiments, the balance of the solid-stateelectrolyte is the first component and the binder.

Other components can include alkali metal ion salts, including lithiumion salts, sodium ion salts, and potassium ion salts. Examples includeLiPF₆, LiTFSI, LiBETI, etc. However, in some embodiments, thesolid-state electrolytes are substantially free of alkali metal ionsalts.

In some embodiments, the electrolyte may include an electrodestabilizing agent that can be used to form a passivation layer on thesurface of an electrode. Examples of electrode stabilizing agents aredescribed in U.S. Pat. No. 9,093,722. In some embodiments, theelectrolyte may include conductivity enhancers, fillers, or organiccomponents as described above.

The composite solid-state electrolytes may be used in any solid-statealkali-ion or alkali-metal battery, including lithium-ion batteries,sodium-ion batteries, lithium-metal batteries, and sodium-metalbatteries. The composite solid-state electrolytes are well-suited forbatteries in which dendrite growth is a concern. For example, in someembodiments, an electrolyte for a lithium metal battery is provided. Thecomposite solid-state electrolytes enable the use of lithium metalanodes by resisting dendrites. The composite solid-state electrolytesmay be used with any cathode material, including sulfur cathodes. Theorganic phase components described above do not dissolve polysulfidesand are suited for use with lithium-sulfur batteries.

A solid film electrolyte composition of the present invention may be ofany suitable thickness depending upon the particular battery design. Formany applications, the thickness may be between 10 microns and 250microns, for example 100 microns. In some embodiments, the electrolytemay be significantly thicker, e.g., on the order of millimeters.

Example loadings for solid-state composite electrodes according toembodiments of the present invention are given below in Table 1.

TABLE 1 Example Loadings for Solid-State Composite Electrolytes % Weightof Examples Total Inorganic Sulfide glass 40%-97.5% ionically 40%-90%conductive 65%-90% particles % Weight of Examples organic phase OrganicPhase First Component HLBH, LBH, 50%-99% 2.5%-60% PDMS with 80%-99%10%-60% molecular 95%-99% 10%-35% weights ranging from 500 g/mol- 50,000g/mol, and mixtures thereof High molecular SEBS, SBS, 1%-50% weightpolymer SIS, SBR, 100 1%-20% binder kg/mol and 1%-5% above, and mixturesthereof

Table 1 provides loadings for three-component compositions for which theorganic phase includes a high molecular weight polymer binder. Fortwo-component compositions, the high end of each example range for thefirst component (99%) is replaced by 100%, with the low end of eachexample range for the binder (1%) replaced by 0.

Electrodes

In one aspect of the invention, electrodes including the solid-statecomposite compositions are provided. The electrodes includetwo-component compositions or three-component compositions as describedabove. The solid-state composite compositions further include anelectrode active material, and optionally, a conductive additive. Forthree-component systems, the high molecular weight polymer binder mayconstitute between 1% and 50% by weight of the organic phase, with thefirst component constituting at least 50% by weight of the organicphase. The organic phase consists essentially of the high molecularweight polymer binder and the first component in some embodiments. Inother embodiments, it may include one or more additional components asdescribed above. Example loadings of embodiments of the presentinvention are given below in Table 2.

TABLE 2 Example Loadings for Solid-State Composite Electrodes % Weightof % Weight of Examples powder Total Inorganic phase - Active MaterialLi₂S, LCO, 30-80% 85-97% electrode powder NCA, graphite, 30-50% siliconConductive Activated 5-25% Additive carbon 10-20% Inorganic Sulfideglass 15-60% ionically 30-50% conductive particles % Weight of Examplesorganic phase Organic Phase First Component HLBH, LBH, 50%-99% 3-15%PDMS with 80%-99% molecular 95%-99% weights ranging from 500 g/mol-50,000 g/mol, and mixtures thereof High molecular SEBS, SBS, 1-50%weight polymer SIS, SBR, 100 1%-20% binder kg/mol and 1%-5% above, andmixtures thereof

Table 2 provides loadings for three-component compositions for which theorganic phase includes a high molecular weight polymer binder. Fortwo-component compositions, the high end of each example range for thefirst component (99%) is replaced by 100%, with the low end of eachexample range for the binder (1%) replaced by 0.

In some embodiments, the solid-state electrodes are cathodes including afirst component, inorganic ionically conductive particles, and an activematerial. In some embodiments, the solid-state electrodes are anodesincluding a first component, inorganic ionically conductive particles,and an active material.

Example cathode active materials include lithium cobalt oxide (LCO),lithium manganese oxide (LMO), lithium nickel cobalt aluminum oxide(NCA), lithium iron phosphate (LFP), and lithium nickel cobalt manganeseoxide (NCM). Example anode active materials include graphite and othercarbon-containing materials, silicon and silicon-containing materials,tin and tin-containing materials, lithium and lithium alloyed metals.

In some embodiments, the solid-state electrodes are sulfur cathodesincluding a first component, inorganic ionically conductive particles,and sulfur-containing active material. In some embodiments, thecomposite solid-state cathodes are incorporated into lithium-sulfurbatteries with the composite solid-state cathodes including a firstcomponent, a high molecular weight polymer binder, inorganic ionicallyconductive particles, lithium sulfide (Li₂S) particles, and a carbonconductive material.

According to various embodiments, the solid-state electrodes are thinfilms having thicknesses of less than 200 microns, and in someembodiments, less than 100 microns. The areal capacity may be between 2mAh/cm² and 5 mAh/cm² n some embodiments.

In one aspect of the invention, electrode/electrolyte bilayers thatinclude the solid-state composite compositions are provided. Thebilayers include a solid-state composite electrode and a solid-statecomposite electrolyte as described above. Each of the ionicallyconductive inorganic particles, the first component, and the highmolecular weight polymer binder (if present) may be independentlyselected for the electrode and the electrolyte, such that each componentof the electrode may be the same or different as that in theelectrolyte. The solid-state electrodes are thin films havingthicknesses of less than about 200 microns, and in some embodiments,less than about 100 microns. The solid-state electrolyte, which contactsthe solid-state electrode, may have a thickness of less than about 200microns. In some embodiments, it is between 5 microns and 50 micronsthick, e.g., between 25 microns and 50 microns thick.

An example of a method of producing a solid-state composite electrode isdescribed in Example 9. An example of a method of producing asolid-state composite electrode/electrolyte bilayer is described inExample 10.

Battery

Provided herein are alkali metal batteries and alkali metal ionbatteries that include an anode, a cathode, and a compliant solidelectrolyte composition as described above operatively associated withthe anode and cathode. The batteries may include a separator forphysically separating the anode and cathode.

Examples of suitable anodes include but are not limited to anodes formedof lithium metal, lithium alloys, sodium metal, sodium alloys,carbonaceous materials such as graphite, and combinations thereof.Examples of suitable cathodes include, but are not limited to cathodesformed of transition metal oxides, doped transition metal oxides, metalphosphates, metal sulfides, lithium iron phosphate, sulfur andcombinations thereof. In some embodiments, the cathode may be a sulfurcathode. Additional examples of cathodes include but are not limited tothose described in Zhang et al., US Pat. App. Pub No. 2012/0082903, atparagraph 178, which is incorporated by reference herein. In someembodiments, an electrode such as a cathode can contain a liquid, suchas described in Y. Lu et al., J. Am. Chem. Soc. 133, 5756-5759 (2011),incorporated by reference herein.

In an alkali metal-air battery such as a lithium-air battery, sodium-airbattery, or potassium-air battery, the cathode may be permeable tooxygen (e.g., mesoporous carbon, porous aluminum, etc.), and the cathodemay optionally contain a metal catalyst (e.g., manganese, cobalt,ruthenium, platinum, or silver catalysts, or combinations thereof)incorporated therein to enhance the reduction reactions occurring withlithium ion and oxygen at the cathode.

In some embodiments, lithium-sulfur cells are provided, includinglithium metal anodes and sulfur-containing cathodes. As noted above, thesolid-state composite electrolytes described herein uniquely enable botha lithium metal anode, by preventing dendrite formation, and sulfurcathodes, by not dissolving polysulfide intermediates Li₂S_(n) that areformed at the cathode during discharge.

A separator formed from any suitable material permeable to ionic flowcan also be included to keep the anode and cathode from directlyelectrically contacting one another. However, as the electrolytecompositions described herein are solid compositions, they can serve asseparators, particularly when they are in the form of a film.

As described above, in some embodiments, the solid compositecompositions may be incorporated into an electrode of a battery. Theelectrolyte may be a compliant solid electrolyte as described above orany other appropriate electrolyte, including liquid electrolyte.

In some embodiments, a battery includes an electrode/electrolytebilayer, with each layer incorporating the ionically conductivesolid-state composite materials described herein.

FIG. 12 shows an example of a schematic of a cell 100 according tocertain embodiments of the invention. The cell 100 includes a negativecurrent collector 102, an anode 104, an electrolyte 106, a cathode 108,and a positive current collector 110. The negative current collector 102and the positive current collector 110 may be any appropriateelectronically conductive material, such as copper, steel, gold,platinum, aluminum, and nickel. In some embodiments, the negativecurrent collector 102 is copper and the positive current collector 110is aluminum. The current collectors may be in any appropriate form, suchas a sheet, foil, a mesh, or a foam. According to various embodiments,one or more of the anode 104, the cathode 108, and the electrolyte 106is a solid-state composite including a first component as describedabove. In some embodiments, each of the anode 104, the cathode 108, andthe electrolyte 106 is two- or three-component solid-state composite, asdescribed above. FIG. 13 shows an example of schematic of a lithiummetal cell as-assembled 200 according to certain embodiments of theinvention. The cell as-assembled 200 includes a negative currentcollector 102, an electrolyte 106, a cathode 108, and a positive currentcollector 110. Lithium metal is generated on first charge and plates onthe negative current collector 102 to form the anode. One or both of theelectrolyte 106 and the cathode 108 may be a two- or three-component asdescribed above. In some embodiments, the cathode 108 and theelectrolyte 106 together form an electrode/electrolyte bilayer asdescribed above. FIG. 14 shows an example of a schematic of a cell 100according to certain embodiments of the invention. The cell 100 includesa negative current collector 102, an anode 104, a cathode/electrolytebilayer 112, and a positive current collector 110.

All components of the battery can be included in or packaged in asuitable rigid or flexible container with external leads or contacts forestablishing an electrical connection to the anode and cathode, inaccordance with known techniques. As noted above, in certainembodiments, the battery packaging may be used to apply a pressure of atleast 1 MPa to the composition.

Example Embodiments

EXAMPLE 1 Textures of Composite Materials Prepared from Sulfide Glassesand Polymers

PDMS sulfide glass compositions and PBD sulfide glass compositions wereprepared and their textures evaluated.

A procedure for the preparation of sulfide glass particles for the PDMSsulfide glass compositions and PBD sulfide glass compositions is asfollows: in an argon filled glovebox, 75 g of 10 mm zirconia balls areplaced into an 80 mL zirconia cup followed by 0.1 g lithium iodide, 1.94g lithium sulfide and 2.96 g phosphorus pentasulfide. The cup is sealed,taken out of the glovebox, and secured in the ball mill. The material ismilled for 30 minutes at 200 rpm to thoroughly mix the componentsfollowed by 18 hours of milling at 400 rpm to react the materials andproduce the sulfide glass. This reaction period is performed in 1 hourincrements, with a 5 minute rest between each hour of milling andreversal of rotation direction between each increment. The cup is thenreturned to the glovebox, and the glass is scraped out and broken intolarge chunks. These glass chunks are returned to the cup with the sameballs and the cups are sealed and returned to the ball mill. The glassis milled for an additional 10 min at 200 rpm to obtain fine particlesof glass. After returning the cup to the glovebox, the glass is sievedthrough #80 mesh and the sieved glass is collected.

A procedure for the preparation of PDMS sulfide glass compositions on a1 g scale is as follows: 0.855 g of the sulfide glass, 0.145 g ofpolydimethylsiloxane polymer (Gelest, Inc.) and 1.25 g of ZrO₂ balls (φ5mm) are placed in a 30 mL polypropylene cup. The cup is equipped with avacuum adapter and placed in a Thinky mixer (ARV-50LED, THINKY) for 10min at 1500 rpm, then manually stirred and mixed for additional 2 min.

A procedure for the preparation of PBD sulfide glass compositions on a 2g scale is as follows: 1.700 g of the sulfide glass, 0.300 g of PBDpolymer (Cray Valley) and 6.2 g of ZrO2 balls (φ5 mm) are placed in a 30mL polypropylene cup. The cup is equipped with a vacuum adapter andplaced in a Thinky mixer (ARV-50LED, THINKY) for 10 min at 1500 rpm,under low vacuum (86 kPa).

Composite materials were prepared from [75Li₂S-25P₂S₅+2% LiI] sulfideglasses and various PDMS polymers. Polymer size and polymer end groupwere varied, and was the presence of a high molecular weight polymerbinder. The PDMS polymers, high molecular weight PDMS binder (ifpresent), and the sulfide glasses were the only constituents of thecompositions. Texture was characterized as shown in Table 3:

TABLE 3 Composite materials prepared from 75Li₂S— 25P₂S₅ + 2% LiI andvarious PDMS polymers Polymer Binder Glass Sample Type wt % Type wt % wt% Texture 1.1 PDMS-OH (0.5k) 15 — — 85 Rubbery 1.2 PDMS-OH (0.6k) 23 — —77 Sticky, flows 1.3 PDMS-OH (0.6k) 15 — — 85 Sticky, rubbery 1.4PDMS-OH (1.1k) 15 — — 85 Rubbery 1.5 PDMS-OH (2.5k) 15 — — 85 Rubbery1.6 PDMS-OH (0.5k) 12 PDMS (110k) 3 85 Rubbery 1.7 PDMS-NH₂ (0.9k) 15 —— 85 Rubbery 1.8 PDMS-NH₂ (0.9k) 15 — — 85 Rubbery 1.9 PDMS-NH₂ (2.5k)20 — — 80 Soft, sticky, flows 1.10 PDMS-NH₂ (2.5k) 18 — — 82 Sticky,rubbery 1.11 PDMS-NH₂ (2.5k) 15 — — 85 Very rubbery 1.12 PDMS-NH₂ (2.5k)12 — — 88 Rubbery 1.13 PDMS-NH₂ (0.9k) 10 PDMS (500k) 5 85 Tougher,rubbery 1.14 PDMS-NH₂ (0.9k) 7.5 PDMS (500k)   7.5 85 Hard Balls 1.15PDMS-NH₂ (0.9k) 5 PDMS (500k) 10  85 Hard Balls

As noted above, the solid-state compositions described herein may have arubbery texture and are not in the form of powder, pebbles or balls. Insome embodiments, they are not sticky and may be characterized ascohesive rather than adhesive. The compositions in rows 1.1, 1.3-1.8,1.11-1.13, 1.16 and 1.17 had desirable rubbery textures. Thecompositions in rows 1.6 and 1.13-1.15 include high molecular weightpolymeric binder and a smaller functionalized polymer.

Solid-state compositions were prepared from [75Li₂S-25P₂S₅+2% LiI]sulfide glasses and various PBD polymers. Glass weight percentage,polymer size and polymer end group were varied. Texture wascharacterized as shown in Table 4.

TABLE 4 Compositions prepared from 75Li₂ S-25P₂S₅+ 2% LiI and variousPBD polymers Polymer Sample Type wt % Texture 2.1 PBD-OH (1.2k) 15Rubbery 2.2 LBH-OH (2k) 15 Rubbery 2.3 LBH-OH (2k) 14 Sticky, rubbery2.4 LBH-OH (2k) 10 Rubbery 2.5 PBD-OH (2.8k) 15 Rubbery 2.6 PBD-epoxy(1.3k) 15 Pebbles 2.7 HLBH-OH (2k) 15 Rubbery

PBD can be represented as shown below with m=number of trans bonds,n=number of vinyl bonds, and o=number of cis bonds. The characteristicsof PBD polymers can vary widely according to the concentration of trans,vinyl and cis bonds.

In the table above, PDB refers to 60/20/20 trans/vinyl/cis and LBHrefers to 22.5/65/12.5. The PBD polymers and the sulfide glasses werethe only constituents of the composites, such that the percentage of thesulfide glass in the compositions was 100% minus the polymer wt %. Thecompositions in Tables 1 and 2 were prepared in accordance with thegeneral procedures described above.

FIG. 1 shows a scanning electron microscope (SEM) image of a pressedpellet of a solid-state composition according to certain embodiments ofthe present invention. The polymer component is a PFPE (Fluorolink D10H)(23 wt %) and the glass is 75Li₂S-25P₂S₅. This composition was preparedin the manner described above for the PDMS and PBD compositions. The SEMimage in FIG. 1 shows that the compositions are uniform, with theparticles distributed evenly.

EXAMPLE 2 Preparation of Solid-State Composite Materials

Solid-state composite materials were prepared by ball milling. Thesecompositions are described below in Table 3 as Samples 3.1-3.5.

To prepare a PFPE sulfide-glass composition (Sample 3.1), the followingprocedure was used. In a glovebox under inert atmosphere, a 80 mLzirconia cup is loaded with 75 g of 10 mm zirconia balls, 3.85 g ofsulfide glass and 1.15 g of diol-terminated PFPE with MW ofapproximately 1500 g/mol. The cup is sealed so that it remains underinert atmosphere for the entire milling time. The cup is secured intothe ball mill and the materials mixed at 200 rpm for 10 minutes. The cupis brought back into the glovebox and the rubbery composite material isscraped from the walls of the cup.

To prepare various PDMS sulfide glass compositions and PBD sulfide glasscompositions (Samples 3.2-3.5), the following procedure was used. In aglovebox under inert atmosphere a 80 mL zirconia cup is loaded with 75 gof 10 mm zirconia balls, 4.25 g of sulfide glass, and 0.75 g of selectedpolymer (see Table 3). The cup is sealed so that it remains under inertatmosphere for the entire milling time. The cup is secured into the ballmill and the materials mixed at 200 rpm for 10 minutes. The cup isbrought back into the glovebox and the rubbery material is scraped fromthe walls of the cup. PDMS used were amino-terminatedpolydimethylsiloxane (PDMS-NH₂ 5 k, Gelest, Inc.) and hydroxy-terminatedpolydimethylsiloxane (PDMS-OH 4.2 k, Gelest, Inc.) and PBD used werehydroxyl-terminated polybutadiene (LBH2000 2.1 k, Cray Valley) andhydrogenated hydroxyl-terminated polybutadiene (HLBH2000 2.1 k, CrayValley)

Solid-state composite materials were prepared by solvent casting. Thesecompositions are described below in Table 3 as Samples 3.6-3.8. Sample3.6 was prepared by the following method: a 30 mL polypropylene cup wasloaded with 2.625 g of the sulfide glass and 2.53 g of 14.8 wt. %mixture of amino-terminated polydimethylsiloxane and SEBS (4:1 w/wratio) in p-xylene. The cup was equipped with a vacuum adapter andplaced in a Thinky mixer (ARV-50LED, THINKY) for 10 min at 1500 rpm. Theslurry was cast on aluminum foil using a doctor blade coater(MSK-AFA-III, MTI). The film was dried under argon for 1 hr and thenunder vacuum for additional 12 hrs. All steps were performed in aglovebox under inert atmosphere (argon).Poly(styrene-b-ethylene/butylene-b-styrene) (SEB S, 118 kDa) obtainedfrom Sigma-Aldrich.

Sample 3.7 was prepared similarly to Sample 3.6. 3.500 g of the sulfideglass and 2.50 g of 20 wt. % mixture of hydroxyl-terminatedpolybutadiene and SEBS (4:1 w/w ratio) in p-xylene were used.

Sample 3.8 was prepared similarly to Sample 3.6. 3.500 g of the sulfideglass and 1.94 g of 26 wt. % mixture of hydrogenated hydroxyl-terminatedpolybutadiene and SEBS (4:1 w/w ratio) in p-xylene were used. Anadditional 0.3 g of p-xylene was added to the mixture before mixing.

Comparative solid-state composite materials were prepared. Thesecompositions are described below in Table 4 as comparative Samples4.1-4.6. Comparative Sample 4.1 was prepared similarly to Sample 3.6.2.377 g of the sulfide glass and 0.50 g of 25 wt. % solution of SEBS inp-xylene was used. An additional 1.25 g of p-xylene was added to themixture before mixing.

Comparative Sample 4.2 was prepared similarly to Sample 3.6. 1.800 g ofthe sulfide glass and 0.80 g of 25 wt. % solution of SEBS in p-xylenewas used. An additional 0.135 g of p-xylene was added to the mixturebefore mixing.

Comparative Sample 4.3 was prepared similarly to Sample 3.6. 1.327 g ofthe sulfide glass and 0.95 g of 25 wt. % solution of SEBS in p-xylenewas used. An additional 0.45 g of p-xylene was added to the mixturebefore mixing.

Comparative Sample 4.4 and 4.5 were also prepared similarly to Sample3.6.

Comparative Sample 4.6 was prepared similarly to Sample 3.1. 2.31 g ofthe glass ceramic (Li7P3S11, MSE Supplies) and 0.69 g of PFPE. Theconductivity of the glass-ceramic was stated as 3.2 mS/cm at 25° C.

The sulfide glass particles for the polymer sulfide glass compositionsin Samples 3.1-3.7 and Comparative Samples 4.1-4.6 were prepared asfollows. In a glovebox under an inert atmosphere each of four 500 mLzirconia cups are loaded with 375 g of 10 mm zirconia balls, 7.04 glithium sulfide, 10.78 g phosphorus pentasulfide, and 7.18 g lithiumiodide. The cups are sealed so that they remain under inert atmospherefor the entire milling time. All four cups are secured into the ballmill, and the mill run at 150 rpm for ½ hour to mix the components. Themilling speed is then increased to 300 rpm for a total active millingtime of 36 hours, with 10 minute pauses every 30 minutes to preventoverheating of the mill. After each pause milling direction reverses.

The cups are brought back into the glovebox, unsealed, and the newlyformed glass electrolyte scraped from the walls of the cup. The glasselectrolyte and balls are returned to their original cups and the sealedcups returned to the ball mill. The electrolyte is ground at 200 rpm for10 minutes. The cups are again returned to the glovebox and the glassremoved from each cup, combined, and sieved to 25 microns. Theconductivity of the glass was measured to be 0.84 mS/cm at 25° C.

EXAMPLE 3 Conductivity Measurements of Samples 3.1-3.8

To measure conductivity of sample, approximately 300 mg of the sampleare loaded into a press with a diameter of 14.8 mm and densified at 300MPa. This pellet is then used to generate several pellets with 0.25″diameter, which are placed in an insulating spacer with diameter 0.25″.Aluminum foil is used as blocking electrodes. The assembly is sealed inair-free pouches in an argon-filled glovebox and placed between twosteel plates fixed together with four screws. Pressure is applied byusing a torque wrench to apply a specified amount torque to each screw.The actual pressure on the sample is measured using pressure-paper (FujiPrescale). Thickness is measured before and after the measurement isperformed using a micrometer. Measurements are performed at roomtemperature. All values, unless otherwise reported, are measured atabout 50 MPa, which correlates to roughly about 3 Nm of torque on eachscrew (easily achieved with hand tools).

Table 5 provides the polymer composition, sample preparation andconductivity of Samples 3.1-3.8. The inorganic conductor for all sampleswas 75Li₂S-25P₂S₅+35% LiI

TABLE 5 Conductivity measurements of composite materials Polymer BinderSample σ Sample Type wt % Type wt % Preparation mS/cm 3.1 PFPE 23 — —Ball Mill 0.54 3.2 PDMS-OH 15 — — Ball Mill 0.62 3.3 PDMS-NH₂ 15 — —Ball Mill 0.65 3.4 LBH2000 15 — — Ball Mill 0.34 3.5 HLBH2000 15 — —Ball Mill 0.37 3.6 PDMS-NH₂ 10 SEBS 2.5 Solvent Cast 0.34 3.7 LBH2000 10SEBS 2.5 Solvent Cast 0.17 3.8 HLBH2000 10 SEBS 2.5 Solvent Cast 0.34

Samples 3.1-3.5 are two component composites of a 75Li₂S-25P₂S₅+35% LiIsulfide glass and a polymer (first component) as described above. (Thevolume % of the PFPE of Sample 3.1 is approximately equal to the volumepercentages of the polymers in Samples 3.2-3.5). Samples 3.2-3.5demonstrate the composite electrolytes work comparable fornon-ion-conducting polymers (PDMS and PBD) as for an ion-conductingPFPE. Notably, no salt was added to the compositions.

Samples 3.6-3.8 are three component composites of the sulfide glass, apolymer (first component), and a solid-state high molecular weightpolymer binder as described above. These samples demonstrate that thecomposite electrolytes work with the inclusion of a high molecularweight polymer binder, which can be important for casting high qualityfilms.

COMPARATIVE EXAMPLE 4 Conductivity Measurements of Comparative Samples4.1-4.6

The conductivities of Samples 4.1-4.4 were measured as described abovein Example 3. Table 6 provides the polymer composition, samplepreparation and conductivity of each Comparative Sample 4.1-4.6.

TABLE 6 Conductivity measurements of comparative composite materialsComp Polymer Binder Sample σ Sample Inorganic Conductor Type wt % Typewt % Preparation mS/cm 4.1 Glass (75Li₂S—25P₂S₅ + 35% LiI) — — SEBS 5Solvent Cast 0.05 4.2 Glass (75Li₂S—25P₂S₅ + 35% LiI) — — SEBS 10Solvent Cast 0.01 4.3 Glass (75Li₂S—25P₂S₅ + 35% LiI) — — SEBS 15Solvent Cast <0.01 4.4 Glass (75Li₂S—25P₂S₅) PBD 10 SEBS 2.5 SolventCast 0.06 200k 4.5 Glass (75Li₂S—25P₂S₅) PBD 12.5 — — Solvent Cast 0.06200k 4.6 Glass Ceramic (Li₇P₃S₁₁) PFPE 23 — — Ball Mill <0.01

Comparative Samples 4.1-4.3 show that without the first component andonly a high molecular weight polymer binder, there is littleconductivity. Comparative Samples 4.1-4.3 can be compared to Samples3.6-3.8 and show the addition of a smaller molecular weight firstcomponent results in higher conductivity under applied pressure.Comparative Samples 4.4 and 4.5 use 200,000 g/mol PBD polymers with(4.4) and without (4.5) a binder, and show that the molecular weight ofthe first component is critical to obtaining conductivity. ComparativeSamples 4.4 and 4.5 can be compared to 2000 g/mol PBD polymers systemsin Table 5.

Comparative Sample 4.6 can be compared to Sample 3.1 and shows that aglass-ceramic inorganic phase results in much lower conductivity than aglass inorganic phase.

EXAMPLE 5 Conductivity vs Applied Pressure of PFPE-Composite (Example3.1)

FIG. 2 shows conductivity as a function of applied pressure for thePFPE-composite described above (Sample 3.1 in Examples 2 and 3).Conductivity increases by an order of magnitude with applied pressure.Notably, the most of the conductivity of the pristine glass particles(.84) is recovered by application of pressure.

EXAMPLE 6 Electrochemical Impedance Spectra of Full Cells IncludingComposite Solid-State Electrolytes With and Without Applied Pressure

FIG. 3 shows a Nyquist plot of electrochemical impedance (EIS) spectraof a cell 340 (glass cathode and pelletized composite electrolyte)according to certain embodiments of the present invention with andwithout pressure applied. A close-up of the pressure curve is also shownin the inset. It should be noted that “without pressure applied” refersto a baseline of 1 atm pressure that results from sealing the assemblyin air-free pouches as described above, and is denoted in the Figure as“ambient.”

The cell 340 was prepared as follows: Ball-milled cathode powder(Li₂S/AC/glass, 45/15/40) was spread on carbon paper current collectorand densified at 50 MPa. A spacer (Mylar, 100 μm) with 5/16″ hole wasplace on top of the cathode powder, followed by a composite electrolytepellet ( 5/16″ in diameter, ˜0.5 mm thick made from Sample 3.1 material)then a disk of lithium-indium alloy anode (˜½″ in diameter). Theassembled stack was sandwiched between two stainless steel disks andtaped with Kapton tape. Finally, aluminum tabs were attached to bothsides and the cell was sealed in a pouch. The cells were measured in thefixture described above.

FIG. 4 shows a Nyquist plot of EIS spectra of cell 341 (film ofcomposite cathode and pelletized composite electrolyte) according tocertain embodiments of the present invention with and without pressureapplied. A close-up of the pressure curve is also shown in the inset. Itshould be noted that “without pressure applied” refers to a baseline of1 atm pressure that results from sealing the assembly in air-freepouches as described above, and is denoted in the Figure as “ambient.”

Cell 341 was prepared as follows: A cathode slurry was prepared frommixing ball-milled cathode powder (Li₂S/AC/glass, 45/15/40), SEBS, andPDMS-NH₂ in xylene and coated on a carbon-coated aluminum currentcollector with areal capacity of about 1 mAh/cm². The final weightpercent of SEBS and PDMS in the cathode were 2% and 5% respectively.Electrodes with a diameter of ¼″ were punched from the currentcollector. A spacer (Mylar, 100 μm) with 5/16″ hole was place on top ofthe cathode, followed by a composite electrolyte pellet ( 5/16″ indiameter, ˜0.5 mm thick made from Sample 3.1 material) then a disk oflithium-indium alloy anode (˜½″ in diameter). The as-assembled stack wassandwiched between two stainless steel disks and taped with Kapton tape.Aluminum tabs were attached to both sides and the cell was sealed in apouch. The cells were measured in the same fixture described above forcell 340.

FIG. 5 shows a Nyquist plot of EIS spectra of cell 342 (cast compositecathode coated with a film of composite electrolyte) according tocertain embodiments of the present invention with and without pressureapplied. A close-up of the pressure curve is also shown in the inset. Itshould be noted that “without pressure applied” refers to a baseline of1 atm pressure that results from sealing the assembly in air-freepouches as described above with reference to cell 340, and is denoted inthe Figure as “ambient.”

Cell 342 was prepared as follows: A layer of composite electrolyte withcomposition identical to Sample 3.6 was solvent-cast from xylenedirectly on top of the cathode. Cathode/electrolyte disks (¾″ indiameter) were punched out of the prepared sheet. Battery assembly wasdone by placing lithium-indium alloy anode (˜ 9/16″ in diameter) ontothe cathode/electrolyte disk. The as-assembled stack was sandwichedbetween two stainless steel disks and taped with Kapton tape. Aluminumtabs were attached to both sides and the cell was sealed in a pouch. Thecells were measured in the same fixture described above with referenceto cell 340.

EXAMPLE 7 Heat Processed Film Conductivities

In a glovebox operating under argon atmosphere, 1.750 g of lithiumsulfide glass (Li₂S:P₂S₅=75:25) was placed in a cup, next, 1.0 g of 25wt. % solution of hydrogenated polybutadiene diol (Krasol HLBH-P 2000,Cray Valley) and poly(styrene-b-ethylene/butylene-b-styrene) (SEBS, 118kDa, Sigma-Aldrich) mixed in 4 to 1 w/w ratio in 1,2,4-trimethylbenzenewas added, followed by additional 0.15 mL of 1,2,4-trimethylbenzene. Thecup was placed in a Thinky mixer (Thinky ARV-SOLED) and mixed at 500 rpmfor 30 mins, and then coated on aluminum foil. Once the solvent hadevaporated, the film was additionally dried under vacuum for 16 hrs. A50×70 mm rectangle was cut out from the dry film, pressed under 6 tonsload using a vertical laminating press for 2 hrs at 25° C. (not hotpressed) or heated to 140° C. (hot-pressed). The conductivities of filmswere measured in as Al|Al symmetrical cells sealed pouches under appliedforces of 0.1 MPa (ambient), 15 MPa and 75 MPa. (The * indicates thevalues taking into account the thickness difference resulting from theapplied pressure.) The results are in Table 7 below.

TABLE 7 Conductivity measurements of composites with and without heatprocessing. 10⁴ · Cond./S · cm⁻¹ Sample Press Applied Force/MPa #Temp./° C. 0.1 15 75* 5.1 25 0.033 0.24 0.95 5.2 0.029 0.31 0.93 5.30.033 0.26 1.00 Average 0.031 ± 0.003 0.27 ± 0.04 0.96 ± 0.04 5.4 1400.72 1.00 1.2 5.5 1.8 2.0 2.0 5.6 0.85 0.94 1.1 5.7 0.64 0.71 1.0Average 1.0 ± 0.5 1.2 ± 0.6 1.3 ± 0.5

All films are processed under pressure. The films processed at 140° C.retain conductivity even after the pressure is released. While, thefilms processed at room temperature show an increase in conductivityunder applied pressure. The films processed at 140° C. show highconductivity even under ambient pressure. This is because the SEBS (2.5wt % of the composite) hardens as the film is cooled, thereby locking inparticle-to-particle contact. In particular, the styrene component ofthe SEBS has a glass transition temperature around 100° C.

FIG. 6 is a plot of conductivity of a heat-processed solid-statecomposite electrolyte film according to certain embodiments of thepresent invention as a function of temperature in a pouch cell with noapplied pressure. The values shown in the plot are the average of threesamples, with the error bars representing the standard deviation. Thecomposition of the solid state composite electrolyte was 87.5 wt % 75:25Li2S:P2S5 glass, 10 wt % HLBH2000, 2.5 wt % SEBS (118 kDa). The samplewas hot-pressed at 140° C. for 2 hours using 17 MPa of pressure.

COMPARATIVE EXAMPLE 8 Heat Processed Comparative Samples 6.1-6.4

Composite films having various compositions were hot-pressed at 140° C.for two hours under 17 MPa of pressure. The compositions and measuredconductivities of Comparative Samples 6.1-6.4 are shown in Table 6,below. All films were 85 wt % Li₂S:P₂S₅ glass and 15 wt % organic phase.Sample 51 represents an average value of multiple samples.

Composition of Organic Applied Force/MPa Phase, wt % of 0.1 15 75*Comments on Mechanical Sample composite electrolyte 10⁻⁴ · Cond./S ·cm⁻¹ Properties 6.1 5 wt. % SEBS (118 kDa) 0.17 ± 0.01 0.36 ± 0.09 0.9 ±0.1 6.2 15 wt. % SEBS <0.01 6.3 10 wt. % PSt (35k), 0.23 0.71 1.34Brittle 5 wt. % SEBS (118 kDa) 6.4 15 wt. % PEO (2M) <0.01 Goodmechanical properties

Sample 6.1 represents average values of composite electrolytes having anorganic phase that is pure high molecular weight polymer binder (SEBS,118 kDa, 5 wt %). Sample 6.1 can be compared to the average of samples5.4-5.7 and shows that even at low loadings, electrolytes having organicphases of pure non-polar high molecular weight polymer binders havesignificantly less ionic conductivity than those having a firstcomponent such as HLBH-2000 g/mol. Sample 6.2 is a composite having 15wt % SEBS and shows that conductivity is negligible for compositeelectrolytes having an organic phase that is pure high molecular weightpolymer binder at higher loadings.

Sample 6.3 is 10 wt % polystyrene (PSt) (35 kDa) and 5 wt % SEBS (118kDa). It can be compared to Sample 6.1 and shows that the addition ofthe first component increases conductivity under applied force.

Sample 6.4 has an organic phase of a polar polymer (PEO-2M). While thecomposite film has good mechanical properties, it is not ionicallyconductive. This demonstrates that polymers having electron donatingbackbones do not work well.

EXAMPLE 9 Preparation of a Composite Cathode

A dry cathode powder can be prepared as follows: Lithium sulfide (Li₂S)and activated carbon (AC) are milled in planetary ball mill (Fritsch)for 36 h at 400 rpm. Sulfide glass is then added to the milling vesseland the contents are milled for an additional 4 hours at 400 rpm. In anexample of embodiment, the final composition is 45/15/40 by weight ofLi₂S/AC/Glass.

The polymeric components of the composite solid-state cathode, includingone or more liquid-like first components (HLBH, LBH, PDMS) and one ormore high molecular weight polymer binders (e.g., SEBS) are dissolved ina non-polar organic solvent (e.g. xylene). This solution is added to thedry cathode powder and mixed in a centrifugal mixer (THINKY) to preparethe electrode slurry. The slurry is cast on carbon-coated aluminum foilcurrent collector by doctor blade technique, and the solvent evaporated.

EXAMPLE 10 Preparation of a Composite Cathode/Electrolyte Bilayer

The polymeric components of the composite electrolyte including one ormore liquid-like first components (e.g., HLBH, LBH, PDMS) and one ormore high molecular weight polymer binders (e.g. SEBS) are dissolved ina non-polar organic solvent (e.g. xylene). This solution is added tosulfide glass particles and mixed in a centrifugal mixer (THINKY) toprepare the electrolyte slurry. The electrolyte slurry is deposited ontothe cathode layer prepared as in Example 9 by doctor blade techniquecreating a bilayer. After solvent evaporation, the bilayer sheet may bedensified by calendering or pressing with or without heating. FIG. 7shows an image of a composite cathode/composite electrolyte bilayeraccording to certain embodiments.

EXAMPLE 11 Preparation and Resting of Full Cells Including CompositeCathode/Electrolyte Bilayers

Cathode/electrolyte disks are punched out of the preparedcathode/electrolyte bilayer sheet from Example 10. Battery assembly isdone by placing lithium-indium alloy anode attached to a copper currentcollector onto the cathode/electrolyte disk. Tabs are attached, and thestack is sandwiched between two stainless steel disks then sealed in apouch. The cell may be placed into a stainless-steel cell fixture wherea known stack-pressure is applied.

FIGS. 8 and 9 show cycling data for Li—In|Composite Electrolyte|Sulfurcells according to certain embodiments of the present invention at threedifferent temperatures (40° C., 25° C., and 0°). FIG. 8 shows dischargecapacity and FIG. 9 shows columbic efficiency (CE). The area of thecells is 1.6 cm² and the loading is 2.0 mAh/cm². A C/5 rate correspondsto 0.36 mAh/cm². FIG. 9 shows very stable room temperature (25° C.)cycling with high capacity utilization. The utilization is good formoderately high loading and percent active material (45% LiS₂). Theresults also show reasonable low-temperature performance for asolid-state cell, higher than what would be expected for apolymer-containing electrolyte. FIG. 9 shows that the CE is near unity.This suggests a fully reversible process, despite the participation ofglass in the redox process.

FIG. 10 shows a voltage profile of a solid-state sulfur cathode in aLi—In|Composite Electrolyte|Sulfur cell according to certain embodimentsof the present invention at C/5 and C/20 discharge rates. The curveprofiles indicate solid-state reactions, without soluble polysulfideintermediates. This permits nearly full utilization of the activematerial. FIG. 11 shows an EIS spectrum of a Li—In|CompositeElectrolyte|Sulfur cell according to certain embodiments of the presentinvention. The plot shows low room-temperature impedance (less than 100Ωcm²). This indicates that there is intimate contact between the coatedlayers and low transfer resistance.

In the description above and in the claims, numerical ranges areinclusive of the end points of the range. For example, “an averagediameter between 0.1 μm and 500 μm,” includes 0.1 μm and 500 μm.Similarly, ranges represented by a dash (e.g., 50%-99%) are inclusive ofthe end points of the ranges.

The foregoing describes the instant invention and its certainembodiments. Numerous modifications and variations in the practice ofthis invention are expected to occur to those skilled in the art. Forexample, while the above specification describes electrolytes andcathodes for alkali ion or alkali metal batteries, the compositionsdescribed may be used in other contexts. Further, the batteries andbattery components described herein are no limited to particular celldesigns. Such modifications and variations are encompassed within thefollowing claims.

The invention claimed is:
 1. A solid-state electrode for use in analkali ion or alkali metal battery, comprising: an inorganic phasecomprising an ionically conductive inorganic material and anelectrochemically active material; and an organic phase comprising ahomogenous mixture of a first component and a binder, wherein the firstcomponent is a non-ionically conductive polymer having a number averagemolecular weight of between 500 g/mol and 50,000 g/mol and the binder isa non-ion conducting polymer having a number average molecular weight ofat least 100 kg/mol.
 2. The solid-state electrode of claim 1, whereinthe ionically conductive inorganic material constitutes between 15% and60% by weight of the inorganic phase, the electrochemically activematerial constitutes between 30% and 80% by weight of the inorganicphase, and the inorganic phase further comprises an electronicallyconductive additive that constitutes between 5% and 25% of the inorganicphase.
 3. The solid-state electrode of claim 1, wherein the firstcomponent constitutes between 50% and 99% by weight of the organicphase, and the binder constitutes between 1% and 50% by weight of theorganic phase.
 4. The solid-state electrode of claim 1, wherein thefirst component is polydimethylsiloxane (PDMS), polybutadiene (PBD),polystyrene, a cyclic olefin polymer.
 5. The solid-state electrode ofclaim 1, wherein the first component is a linear polymer having endgroups selected from cyano, thiol, amide, amino, sulfonic acid, epoxy,carboxyl, or hydroxyl groups.
 6. The solid-state electrode of claim 1,wherein the inorganic phase is dispersed in a matrix of the organicphase.
 7. The solid-state electrode of claim 1, wherein the firstcomponent has a glass transition temperature (Tg) of less than −50° C.8. The solid-state electrode of claim 7, wherein the binder has a glasstransition temperature greater than 70° C.
 9. The solid-state electrodeof claim 1, wherein the inorganic phase constitutes at least 85% byweight of the solid-state electrode.
 10. The solid-state electrode ofclaim 1, wherein the organic phase constitutes between 3% and 15% byweight of the solid-state electrode.
 11. The solid-state electrode ofclaim 1, wherein the electrochemically active material is selected fromthe group consisting of lithium cobalt oxide (LCO), lithium manganeseoxide (LMO), lithium nickel cobalt aluminum oxide (NCA), lithium ironphosphate (LFP) and lithium nickel cobalt manganese oxide (NCM).
 12. Thesolid-state electrode of claim 1, wherein the electrochemically activematerial is selected from the group consisting of a carbon-containingmaterial, a silicon-containing material, a tin-containing material,lithium, or a lithium alloyed metal.
 13. The solid-state electrode ofclaim 1, wherein the first component and binder are soluble in anon-polar organic solvent.
 14. The solid-state electrode of claim 1,wherein the electrochemically active material is a silicon-containingmaterial.
 15. A solid-state electrode for use in an alkali ion or alkalimetal battery, comprising: an inorganic phase comprising an ionicallyconductive inorganic material and an electrochemically active material;and an organic phase comprising a first component and a binder, whereinthe first component is a non-ionically-conductive polymer having anumber average molecular weight of between 500 g/mol and 50,000 g/moland the binder is a non-ion conducting polymer having a number averagemolecular weight of at least 100 kg/mol, and wherein the binder issoluble in a non-polar organic solvent.
 16. The solid-state electrode ofclaim 15, wherein the non-polar organic solvent is p-xylene.
 17. Thesolid-state electrode of claim 15, wherein the inorganic phase furthercomprises an electronically conductive additive.
 18. The solid-stateelectrode of claim 17, wherein the ionically conductive inorganicmaterial constitutes between 15% and 60% by weight of the inorganicphase, the electrochemically active material constitutes between 30% and80% by weight of the inorganic phase, and the electronically conductiveadditive constitutes between 5% and 25% of the inorganic phase.
 19. Thesolid-state electrode of claim 15, wherein the first componentconstitutes between 50% and 99% by weight of the organic phase, and thebinder constitutes between 1% and 50% by weight of the organic phase.20. The solid-state electrode of claim 15, wherein the electrochemicallyactive material is a silicon-containing material.